SPC MCD 231025
TXZ000-231230-
MESOSCALE DISCUSSION 2351
NWS STORM PREDICTION CENTER NORMAN OK
0425 AM CST MON DEC 23 2002
AREAS AFFECTED...PORTIONS OF CENTRAL/SRN TX
CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 231025Z - 231230Z
IF STORMS CAN BECOME SURFACE BASED...THERE WILL BE A TORNADO
THREAT IN THE VICINITY OF THE NWD MOVING SURFACE WARM FRONT OVER
CENTRAL/SRN TX. CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED
FOR AN INCREASED POTENTIAL FOR SURFACE BASED STORMS AND POSSIBLE
TORNADO WATCH.

LATEST SURFACE MAP SHOWS A WARM FRONT EXTENDING FROM NORTH OF SAT
TO NORTH OF HOU WITH LOW-MID 60F SURFACE DEWPOINTS ALONG AND
SOUTH OF THIS BOUNDARY. NUMEROUS STORMS HAVE DEVELOPED NORTH OF
THE WARM FRONT /N OF SAT/AUS AREA/ WITHIN STRONG LOW-LEVEL WAA.
NEW STORMS HAVE DEVELOPED SOUTH OF THE BOUNDARY OVER ATASCOSA AND
WILSON COUNTIES DURING THE LAST 15-30 MINUTES...WITH OTHER SMALL
SHOWERS DEVELOPING ALONG THE GULF COAST NEAR CRP. MUCH OF THIS
CONVECTION IS ALONG AND WEST OF THE STRONGEST /40 KT/ SLY LOW-
LEVEL FLOW. LOW AND MID LEVEL SHEAR VALUES SUPPORT SUPERCELLS
WITH TORNADOES WITHIN THE WARM SECTOR. MODELS SUGGEST SHEAR
PARAMETERS INCREASE THROUGH THE MORNING HOURS EWD ALONG BOUNDARY.

..PETERS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
28629820 28679877 30229893 30659789 30799657 29739612
29119658
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231131
SPC MCD 231131
NMZ000-TXZ000-OKZ000-231700-
MESOSCALE DISCUSSION 2352
NWS STORM PREDICTION CENTER NORMAN OK
0531 AM CST MON DEC 23 2002
AREAS AFFECTED...ERN NM...TX PANHANDLE...FAR WRN OK
CONCERNING...HEAVY SNOW

VALID 231131Z - 231700Z
SNOWFALL RATES ARE EXPECTED TO INCREASE TO AT LEAST 1 IN/HR
THROUGH THE LATE MORNING HOURS.

MULTIPLE FORCING MECHANISMS CURRENTLY IN PLACE AHEAD OF UPPER
TROUGH. LOW LEVEL WARM AIR ADVECTION ALONG WITH FRONTOGENETICAL
FORCING WILL CONTINUE TO FEED ELEVATED THUNDERSTORMS OVER N
TX...SOME OF WHICH WILL LIKELY MAKE IT INTO THE TX PANHANDLE AND
WRN OK AS THUNDER SNOW. LATEST RUC AND ETA MODELS SHOW HEAVIEST
PRECIPITATION FROM 12-15Z IN THE DISCUSSION AREA. THIS AGREES
WITH LATEST PRECIPITATION TRENDS. PERIODICALLY EJECTING
VORTICITY MAXIMA WILL LIKELY ENHANCE SNOWFALL RATES AS THEY
BECOME SUPERIMPOSED ATOP LOW LEVEL FORCING BETWEEN 12-18Z.
EXPERIMENTAL P-TYPE ALGORITHMS FORECAST SNOW N OF A LBB-CDS-CSM
LINE THROUGH 15Z...WITH A GRADUAL CHANGEOVER OCCURRING IN AREAS
SE THEREAFTER.


..JEWELL.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
35339938 34870020 34580115 33860301 35480321 35880231
36160088 36159973 35939951
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231313
SPC MCD 231313
TXZ000-231515-
MESOSCALE DISCUSSION 2353
NWS STORM PREDICTION CENTER NORMAN OK
0713 AM CST MON DEC 23 2002
AREAS AFFECTED...CENTRAL AND SOUTHEAST TX
CONCERNING...TORNADO WATCH 797...

VALID 231313Z - 231515Z
PARAMETERS REMAIN FAVORABLE FOR TORNADOES THIS MORNING OVER
PORTIONS OF CENTRAL AND SOUTHEAST TX.

REGIONAL RADARS CONTINUE TO INDICATE STRONG LOW-MID LEVEL
ROTATION WITH TORNADIC SUPERCELL MOVING NEWD AT 30 KT THROUGH ERN
TRAVIS COUNTY. THIS STORM IS AT THE TRIPLE POINT OF VERY MOIST
GULF INFLOW...AND A SURFACE BOUNDARY EXTENDING E FROM A SURFACE
LOW AT JCT TO JUST NORTH OF HOU. A SECOND BOUNDARY EXTENDS NEWD
FROM THE VICINITY OF THE TRAVIS COUNTY STORM INTO NRN LA /S OF
SHV/. ENVIRONMENT REMAINS CONDUCIVE TO TORNADO DEVELOPMENT WITH
0-1 KM SRH OVER THE WW RANGING FROM 250-350 M2/S2 WITHIN
MOIST/UNSTABLE BOUNDARY.

CURRENT SATELLITE IMAGERY SUGGESTS THAT STRONG SHORTWAVE TROUGH
IS EJECTING EASTWARD INTO SOUTH CENTRAL TX. UVVS OVER TOP OF
MOIST/ UNSTABLE AIRMASS WILL PROMOTE DEVELOPMENT OF STRONG/SEVERE
STORMS FOR SEVERAL MORE HOURS.


..PETERS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
28669888 30049888 30839716 31629544 30249544 28879544
28089716 27299888
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231332
SPC MCD 231332
TXZ000-LAZ000-231600-
MESOSCALE DISCUSSION 2354
NWS STORM PREDICTION CENTER NORMAN OK
0732 AM CST MON DEC 23 2002
AREAS AFFECTED...SERN TX...SWRN LA
CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 231332Z - 231600Z
WW MAY BE REQUIRED E OF WW 797 WITHIN THE NEXT FEW HOURS.
LATEST SURFACE ANALYSIS INDICATED PRESSURE FALLS AROUND 1 MB
DURING THE PAST HOUR OVER SERN TX AS WARM FRONT MOVES RAPIDLY
NWD. MID 60S F DEWPOINTS WERE ALREADY INTO THE HOUSTON
AREA...AND THIS FRONT WILL LIFT THROUGH THE LCH AREA AS LOW LEVEL
INVERSION HEIGHTS ARE LESS THAN 400 FEET (SEE 12Z LCH SOUNDING).
BOUNDARY LAYER WINDS ARE EXPECTED TO VEER RAPIDLY OVER THE NEXT
SEVERAL HOURS AS LOW DEEPENS...ALLOWING WARM FRONT TO MOVE WELL
INLAND NEAR LFK BY 18Z. STRONG SHEAR PROFILES WILL SUPPORT THE
THREAT OF TORNADOES AS WELL AS DAMAGING WINDS.


..JEWELL.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
29059519 29589538 31229538 31429408 30619311 29599251
29729376
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231634
SPC MCD 231634
TXZ000-231830-
MESOSCALE DISCUSSION 2355
NWS STORM PREDICTION CENTER NORMAN OK
1034 AM CST MON DEC 23 2002
AREAS AFFECTED...SE TX
CONCERNING...TORNADO WATCH 798...

VALID 231634Z - 231830Z
TORNADO POTENTIAL WILL REMAIN GREATEST NEXT 2-3 HOURS WITH
SUPERCELL MOVING NEWD ACROSS PORTIONS AUSTIN/WASHINGTON COUNTIES
AS OF 1615Z. THIS ACTIVITY IS EXPECTED TO CONTINUE MOVING NEWD
AND SHOULD CROSS NEWD MOVING WARM FRONT NEAR UTS.

MEANWHILE...OTHER SUPERCELLS MAY DEVELOP AMIDST LOW-CAPE BUT ALSO
WEAKLY CAPPED WARM SECTOR...AND MOVE NNEWD TO NEWD ACROSS
PORTIONS SE TX WITH TORNADO POTENTIAL.

SURFACE MESOANALYSIS SHOWS WARM FRONT EXTENDING EWD FROM LOW NEAR
JCT...ACROSS NRN PORTIONS AUS METRO...TO NEAR CLL...CXO...ARA.
FRONT SHOULD CONTINUE MOVING INLAND 10-20 KT ACROSS SE TX AND LA.
LOW-MIDLEVEL SHEAR IS FAVORABLE FOR POTENTIALLY TORNADIC
SUPERCELLS ALL ACROSS WARM SECTOR -- WHICH WILL SPREAD NWD ACROSS
MORE OF WW AREA WITH TIME. HOWEVER...PRIND TORNADO POTENTIAL
WILL BE RELATIVELY HIGH NEAR WARM FRONT WHERE BACKED SURFACE FLOW
CONTRIBUTES TO MAXIMA IN CONVERGENCE...BOUNDARY LAYER VORTICITY
AND 0-1 KM AGL SHEAR. AVAILABLE VWP/PROFILER DATA INDICATES
300-500 J/KG 0-3 KM SRH ALONG WARM FRONT...250-350 J/KG SWD TO
UPPER TX COAST.


..EDWARDS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
30689367 29609367 29129550 28639733 29729733 30809733
31299550 31779367
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231650
SPC MCD 231650
OKZ000-232045-
MESOSCALE DISCUSSION 2356
NWS STORM PREDICTION CENTER NORMAN OK
1050 AM CST MON DEC 23 2002
AREAS AFFECTED...WRN/NRN/CNTRL OK
CONCERNING...HEAVY SNOW

VALID 231650Z - 232045Z
SNOWFALL RATES BETWEEN 1-2 IN/HR ARE EXPECTED FOR THE NEXT FEW
HOURS IN PORTIONS OF WRN/NRN/AND CNTRL OK.

RECENT WV/IR IMAGERY INDICATES PRIMARY AREA OF COOLING CLOUD TOPS
PRESENTLY LOCATED FROM ERN TX...NWD THRU ERN OK/WRN ARK...INTO
PARTS OF NRN/NERN OK. NOTICEABLE DRY SLOTTING IS OCCURRING FROM
DRT TO JCT..NWD TO MWL AND SPS AS STRONG 110-130 KT 250MB JET
CORE OVERSPREADS THE REGION. STRONG DYNAMICAL COOLING IS THE
PRIMARY MECHANISN THAT HAS BEEN RESPONSIBLE FOR THE RAPID SURFACE
COOLING AS 23/12Z OUN SOUNDING INDICATED TEMPERATURES ABOVE
FREEZING FROM THE SFC THRU AROUND 850MB. THIS TREND IS EXPECTED
TO CONTINUE THRU THE NEXT SEVERAL HOURS AS INTENSE
FRONTOGENETICAL LIFT IN THE 850-700MB LAYER WILL COMBINE WITH
MOIST PROFILES AND STRONG DYNAMICS TO YIELD AREAS OF HEAVY
SNOWFALL RATES THRU THE EARLY TO MID AFTERNOON.

HOWEVER...RECENT LIGHTNING DATA AND WV IMAGERY INDICATE LARGE
SWATH OF POSITIVE STRIKES...WHICH LIKELY AIDED THE RAPID
ATMOSPHERIC COOLING THE PAST FEW HOURS...HAS DECREASED
DRAMATICALLY AS PROFILER DATA SHOWS THAT DESCENDING AXIS OF UPPER
LVL JET CORE IS ALREADY SURGING THRU MUCH OF THE DISCUSSION AREA.
THE DEPARTURE OF THIS FEATURE...THE DECREASING COVERAGE OF
LIGHTNING STRIKES...DRY SLOTTING FEATURE...AND LACK OF A
WIDESPREAD REGION OF COOLING CLOUD TOPS UPSTREAM SUGGESTS THAT
AREAS OF HEAVY SNOWFALL RATES SHOULD BE RATHER SHORTLIVED BEFORE
TURNING TO JUST A STEADY LIGHT SNOW BY MID-LATE AFTERNOON IN THE
DISCUSSION AREA.


..NADEN.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
34509951 34599960 34909956 35339928 35799875 36519760
36819677 36159652 34489783
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231653
SPC MCD 231653
TXZ000-LAZ000-232100-
MESOSCALE DISCUSSION 2357
NWS STORM PREDICTION CENTER NORMAN OK
1053 AM CST MON DEC 23 2002
AREAS AFFECTED...PORTIONS E TX AND NWRN LA
CONCERNING...HEAVY RAINFALL

VALID 231653Z - 232100Z
HEAVY RAINFALL -- WITH HIGHLY VARIABLE RATES OF UP TO 2.5
INCHES/HOUR -- SHOULD AFFECT PORTIONS E TX AND NWRN LA FROM UTS
AREA NNEWD TOWARD GGG/SHV THROUGH AT LEAST 20Z AS TSTM COMPLEX
NOW OVER SE AND E-CENTRAL TX SHIFTS NEWD. ECHO TRAINING AND
EMBEDDED HP SUPERCELLS WILL CONTRIBUTE TO HEAVY RAIN HAZARD.
SURFACE ANALYSIS SHOWS WARM FRONT ROUGHLY FROM JUST N AUS EWD
ACROSS CLL/UTS REGION THEN ESEWD TO NEAR ARA. GREATEST RAINFALL
WILL REMAIN N OF WARM FRONT IN REGIME OF BOTH STRONG LOW LEVEL
WAA/ISENTROPIC ASCENT AND INCREASING ELEVATED MUCAPE.
VWP/PROFILER WINDS AND RUC FORECAST SOUNDINGS INDICATE 40-50 KT
LLJ ABOVE FRONTAL SURFACE WILL CONTINUE TO PROVIDE FAVORABLE SR
INFLOW AND TO ADVECT MOISTURE OVER THIS REGION AS WELL. MEAN
MIXING RATIOS SHOULD INCREASE FROM AROUND 7.5 TO NEAR 9 G/KG
THROUGH DISCUSSION PERIOD...WITH PW IN 1.25-1.5 INCH RANGE. WITH
CONTINUED LARGE SCALE FORCING AND ASSOCIATED WARMING OF LOW
LEVELS ABOVE BOUNDARY LAYER...MUCAPE SHOULD INCREASE TO 1000-1500
J/KG RANGE AS FAR N AS I-20 BY 21Z.


..EDWARDS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
32259359 31689388 30879463 30729550 30999608 32739475
32979401 32519354
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231702
SPC MCD 231702
OKZ000-232100-
MESOSCALE DISCUSSION 2358
NWS STORM PREDICTION CENTER NORMAN OK
1102 AM CST MON DEC 23 2002
AREAS AFFECTED...WRN/NRN/CNTRL OK
CONCERNING...HEAVY SNOW

VALID 231702Z - 232100Z
SNOWFALL RATES BETWEEN 1-2 IN/HR ARE EXPECTED FOR THE NEXT FEW
HOURS IN PORTIONS OF WRN/NRN/AND CNTRL OK.

RECENT WV/IR IMAGERY INDICATES PRIMARY AREA OF COOLING CLOUD TOPS
PRESENTLY LOCATED FROM ERN TX...NWD THRU ERN OK/WRN ARK...INTO
PARTS OF NRN/NERN OK. NOTICEABLE DRY SLOTTING IS OCCURRING FROM
DRT TO JCT..NWD TO MWL AND SPS AS STRONG 110-130 KT 250MB JET
CORE OVERSPREADS THE REGION. STRONG DYNAMICAL COOLING IS THE
PRIMARY MECHANISN THAT HAS BEEN RESPONSIBLE FOR THE RAPID SURFACE
COOLING AS 23/12Z OUN SOUNDING INDICATED TEMPERATURES ABOVE
FREEZING FROM THE SFC THRU AROUND 850MB. THIS TREND IS EXPECTED
TO CONTINUE THRU THE NEXT SEVERAL HOURS AS INTENSE
FRONTOGENETICAL LIFT IN THE 850-700MB LAYER WILL COMBINE WITH
MOIST PROFILES AND STRONG DYNAMICS TO YIELD AREAS OF HEAVY
SNOWFALL RATES THRU THE EARLY TO MID AFTERNOON.

HOWEVER...RECENT LIGHTNING DATA AND WV IMAGERY INDICATE LARGE
SWATH OF POSITIVE STRIKES...WHICH LIKELY AIDED THE RAPID
ATMOSPHERIC COOLING THE PAST FEW HOURS...HAS DECREASED
DRAMATICALLY AS PROFILER DATA SHOWS THAT DESCENDING AXIS OF UPPER
LVL JET CORE IS ALREADY SURGING THRU MUCH OF THE DISCUSSION AREA.
THE DEPARTURE OF THIS FEATURE...THE DECREASING COVERAGE OF
LIGHTNING STRIKES...DRY SLOTTING FEATURE...AND LACK OF A
WIDESPREAD REGION OF COOLING CLOUD TOPS UPSTREAM SUGGESTS THAT
AREAS OF HEAVY SNOWFALL RATES SHOULD BE RATHER SHORTLIVED BEFORE
TURNING TO JUST A STEADY LIGHT SNOW BY MID-LATE AFTERNOON IN THE
DISCUSSION AREA.


..NADEN.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231856
SPC MCD 231856
TXZ000-LAZ000-232100-
MESOSCALE DISCUSSION 2359
NWS STORM PREDICTION CENTER NORMAN OK
1256 PM CST MON DEC 23 2002
AREAS AFFECTED...SE TX AND SW LA
CONCERNING...TORNADO WATCH 798...

VALID 231856Z - 232100Z
THREAT FOR SUPERCELLS/TORNADOES STILL EXISTS OVER MUCH OF WW...IS
INCREASING OVER SW LA...AND SHOULD CONTINUE PAST SCHEDULED 21Z
EXPIRATION OVER PORTIONS SE TX. THEREFORE...ADDITIONAL TORNADO
WW ISSUANCE IS ANTICIPATED IN THIS REGION BEFORE 21Z.
SEVERAL TORNADO AND WIND DAMAGE REPORTS HAVE COME FROM SUPERCELL
NOW NW OF UTS....ALONG WARM FRONT. SURFACE MESOANALYSIS SHOWS
THIS FRONT CONTINUING TO LIFT SLOWLY NWD ACROSS S-CENTRAL/SE
TX...AND WAS ROUGHLY ALONG A LINE FROM JCT-BMQ-UTS-ARA. AIR MASS
ALONG AND S OF FRONT GENERALLY IS DESTABILIZING BASED ON 18Z
RAOBS AND RUC FORECAST SOUNDINGS...WITH MLCAPE OVER 3000 J/KG AT
CRP...2000 J/KG AT VCT AND 1000-1500 J/KG BETWEEN LCH-IAH-UTS
DURING NEXT 1-2 HOURS. VWP/PROFILER DATA INDICATES 300-500 J/KG
SRH IN 0-3 KM AGL LAYER OVER REGION...EXCEPT NEAR WRN EDGE WW
WHERE SURFACE FLOW IS VEERING IN RESPONSE TO PRESSURE FALLS
FARTHER NE.

GREATEST TORNADO POTENTIAL SHOULD REMAIN INVOF WARM FRONT --
WHERE LOW LEVEL SHEAR AND FORCING WILL REMAIN RELATIVELY LARGE.
HOWEVER...POTENTIALLY TORNADIC SUPERCELLS ARE POSSIBLE IN WARM
SECTOR AS WELL. MOST PROBABLE AREAS FOR NEW SUPERCELL
DEVELOPMENT APPEAR TO BE
1. BAND OF SLOWLY INTENSIFYING CONVECTION NOW EVIDENT FROM VCT
AREA NEWD TOWARD CXO. THIS ACTIVITY IS LOCATED IN PRONOUNCED
SURFACE CONFLUENCE REGION AND WILL SHIFT EWD OVER HOU AREA.
2. ISOLATED CELLS MOVING ONSHORE SWRN LA AND EXTREME SERN
TX...WHERE AIR MASS IS LIKEWISE BECOMING MORE UNSTABLE AND
STRONGLY SHEARED.


..EDWARDS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
31239366 31089293 30549208 29739124 29309125 29739368
31229365
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231912
SPC MCD 231912
OKZ000-KSZ000-MOZ000-ARZ000-232315-
MESOSCALE DISCUSSION 2360
NWS STORM PREDICTION CENTER NORMAN OK
0112 PM CST MON DEC 23 2002
AREAS AFFECTED...NERN OK...SERN KS...SWRN MO...NWRN AR
CONCERNING...HEAVY SNOW

VALID 231912Z - 232315Z
HEAVY SNOWFALL RATES BETWEEN 1-2 IN/HR ARE LIKELY AT TIMES FROM
NERN OK/SERN KS INTO NWRN AR/SWRN MO THRU 23/22-23Z. THE HEAVIER
RATES ARE EXPECTED TO DIMINISH FROM SW TO NE THRU THE LATER
AFTERNOON HOURS.

RECENT SFC ANALYSIS SHOWS TEMPERATURES CONTINUE TO WET BULB DOWN
TO/AROUND FREEZING IN PARTS OF SWRN MO AS LARGE SWATH OF MOISTURE
CONTINUES TO ADVECT NEWD. RECENT DROP OF 6 DEGREES IN TWO HOURS
NOTED AT JLN IN SWRN MO AS MOST STATIONS IN THE DISCUSSION AREA
ARE EXPECTED TO DROP TO BELOW/AROUND FREEZING OVER THE NEXT FEW
HOURS. UTILIZING TRACKING/TIMING MECHANISM FOR SWRN EDGE OF
PRECIPITATION SHIELD YIELDS ENDING TIMES FOR HEAVIER SNOWFALL
FROM 23/2130Z IN NERN OK TO AROUND 23/23Z IN SWRN MO. SIGNIFICANT
MID-LVL DRYING NOTED ON IR/WY IMAGERY SUGGESTS WRN PORTIONS OF
THE DISCUSSION AREA WILL BE THE FIRST TO EXPERIENCE THE DEMISE OF
PRECIPITATION WHILE AREAS IN NWRN AR/SWRN MO WILL LIKELY
EXPERIENCE SEVERAL MORE HOURS OF MODERATE TO HEAVY SNOWFALL. THE
HEAVIEST SNOWFALL RATES THRU THE FCST PERIOD WILL LIKELY BE
ACROSS THE AFOREMENTIONED AREAS OF NWRN AR/SWRN MO.

..NADEN.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
37289607 37919584 38359448 38189339 37509246 36699197
35049289 34949599 36449638 37009634
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 232027
SPC MCD 232027
TXZ000-232330-
MESOSCALE DISCUSSION 2361
NWS STORM PREDICTION CENTER NORMAN OK
0227 PM CST MON DEC 23 2002
AREAS AFFECTED...S-CENTRAL TX...W AND SW OF WW 799
CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 232027Z - 232330Z
TSTMS ARE EXPECTED TO DEVELOP AND INCREASE IN COVERAGE/INTENSITY
OVER PORTIONS S-CENTRAL TX THROUGH 00Z...MAIN THREATS INITIALLY
BEING DAMAGING WIND AND LARGE HAIL. WW MAY BE REQUIRED LATER
THIS AFTERNOON.

STRONG LARGE SCALE ASCENT IS EXPECTED TO SPREAD ACROSS THIS
REGION AHEAD OF NWRN MEX/SWRN CONUS MID-UPPER LEVEL TROUGH. THIS
IS EVIDENT ALREADY IN EXTENSIVE FIELD OF APPARENTLY HIGH-BASED
TCU AND ISOLATED CB OVER TX BIG BEND REGION SWD/SEWD ACROSS
HIGHER TERRAIN OF NRN COAHUILA. THIS ACTIVITY IS BEHIND SURFACE
DRYLINE ANALYZED OVER NERN MEX...EXTENDING SWD FROM JUST S DRT.
COLD FRONT HAS JUST PASSED THRU DRT AND SHOULD CONTINUE MOVING
SEWD ACROSS S-CENTRAL TX AND LOWER RIO GRANDE VALLEY DURING
REMAINDER AFTERNOON. MODIFIED RUC SOUNDINGS INDICATE VERY STEEP
LAPSE RATES AOA 8.5 DEG C/KM AND 300-800 J/KG MUCAPE ABOVE
POST-FRONTAL AIR MASS -- SUPPORTING POTENTIAL FOR TSTMS WITH
LARGE HAIL. SOME OF THIS CONVECTION MAY REACH MOIST SECTOR W OF
SAT BEFORE COLD FROPA -- WHICH WOULD SUBSTANTIALLY INCREASE LARGE
HAIL/DAMAGING WIND THREAT AMIDST NEARLY UNIDIRECTIONAL DEEP-LAYER
FLOW PROFILES.

ADDITIONAL CONVECTION DEVELOPING ALONG FRONT FARTHER N OVER SRN
HILL COUNTRY SHOULD BE UNDERCUT AND REMAIN IN LAYER OF ELEVATED
INSTABILITY. CONVERGENCE ALONG FRONT IS BEING REDUCED BY VEERED
MOIST SECTOR FLOW -- WITH WLY TO SWLY WINDS OBSERVED AROUND SAT.

..EDWARDS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
28440185 29700201 30620016 31039769 29999740 27499945
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 232121
SPC MCD 232121
ARZ000-LAZ000-TXZ000-240045-
MESOSCALE DISCUSSION 2362
NWS STORM PREDICTION CENTER NORMAN OK
0321 PM CST MON DEC 23 2002
AREAS AFFECTED...N-CENTRAL/NERN LA...SMALL PARTS OF E TX AND SERN
AR
CONCERNING...HEAVY RAINFALL

VALID 232121Z - 240045Z
RAINFALL RATES COMMONLY 1.5-2 INCHES/HOUR...AND LOCALLY
APPROACHING 3 INCHES/HOUR IN MOST INTENSE TSTM CORES...ARE
EXPECTED FROM TOLEDO BEND RESERVOIR REGION NEWD ACROSS
N-CENTRAL/NERN LA AND PORTIONS SERN AR THROUGH AT LEAST 00Z.
SCATTERED TO NUMEROUS TSTMS -- SOME OF WHICH WILL BE SUPERCELLS
WITH VERY HEAVY LOCALIZED RAIN RATES -- ARE EXPECTED TO MOVE
ACROSS THIS REGION WITH CELL MERGERS AND TRAINING OF CORES
AUGMENTING THE HAZARD.

SURFACE ANALYSIS SHOWS DOUBLE FRONTAL STRUCTURE -- WITH
INTENSIFYING NRN BAROCLINIC ZONE ROUGHLY ALONG JAN-ESF LINE...AND
ORIGINAL/MARINE FRONT STILL EVIDENT FROM S OF BVE WNWWD PAST ARA
TO NEAR LFK. FRONTS SHOULD GRADUALLY CONSOLIDATE OVER N-CENTRAL
LA NEXT SEVERAL HOURS...WITH INTENSIFYING LOW LEVEL ASCENT.
VWP/PROFILERS AND RUC FORECAST SOUNDINGS INDICATE VERY MOIST
45-55 KT LLJ WILL SUPPORT CONTINUED DEVELOPMENT OF TSTMS OVER
THIS REGION. MUCAPE AND LOW LEVEL MOISTURE CONTENT SHOULD
CONTINUE TO INCREASE THROUGH REMAINDER OF AFTERNOON INTO EARLY
EVENING...WITH PW IN 1.25-1.5 INCH RANGE. WEAK CAPPING SHOULD
CONTRIBUTE TO DENSE CONVECTIVE COVERAGE AND REPEATED PASSAGE OF
HEAVY RAIN CORES OVER SOME LOCALES.


..EDWARDS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
31589398 33349269 33639165 33329112 32379146 31389228
30559370 30549370
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 232136
SPC MCD 232136
MOZ000-ARZ000-ILZ000-240330-
MESOSCALE DISCUSSION 2363
NWS STORM PREDICTION CENTER NORMAN OK
0336 PM CST MON DEC 23 2002
AREAS AFFECTED...MO AR IL
CONCERNING...HEAVY SNOW

VALID 232136Z - 240330Z
SNOWFALL RATES AROUND AN INCH AN HOUR AT TIMES APPEAR LIKELY FOR
PARTS OF SCNTRL AND ERN MO INTO SRN IL INCLUDING AREAS JUST SOUTH
OF THE ST. LOUIS METRO AREA.

LATEST RADAR/VIS IMAGERY INDICATES W-E ORIENTED BANDING TAKING
SHAPE ACROSS SRN/SCNTRL MO INTO EXTREME SRN IL. THIS IS LIKELY A
RESPONSE TO STRENGTHENING 600-700MB FRONTOGENESIS RECOGNIZED BY
THE 23/18Z RUC AS STRONG 850 MB WAA CONTINUES TO DRIVE NWD FROM
LA/ARK INTO THE DISCUSSION AREA. RECENT SFC DATA SHOWS FREEZING
LINE ROUGHLY FROM UNO NNEWD TO VIH BUT EXPECT AREAS FURTHER EAST
BETWEEN CGI AND STL TO WET BULB DOWN TOWARDS FREEZING THE NEXT
FEW HOURS.

ALTHOUGH...MESOSCALE BANDING APPEARS TO BE WEAKENING SOME
ATTM...BELIEVE W-E ORIENTED DEFORMATION AXIS WILL RESTRENGTHEN IN
THE NEXT FEW HOURS AS ADDITIONAL MOISTURE ADVECTS NNEWD INTO
REGION. BOTH SGF AND LITTLE ROCK VADS REVEAL DEEP BACKING WAA
PROFILES ABOVE COLDER ELY SURFACE FLOW AND 850MB LLJ IS PROGGED
TO FOCUS FROM THE GULF COAST NWD THRU ARK/MS INTO THE DISCUSSION
AREA BETWEEN 23/21Z AND 24/03Z YIELDING A PLETHORA OF BOUNDARY
LAYER MOISTURE. AREA OF STRONGEST VERTICAL MOTION AND HEAVIEST
SNOWFALL RATES WILL BE ACROSS SRN/SCNTL MO POKING EWD INTO SRN IL
AS WELL AS IN PARTS OF NRN/NCTRL ARK WHERE A QUICK CHANGEOVER TO
SNOW IS EXPECTED TO OCCUR.


..NADEN.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
38579151 38469084 38268987 37898876 37748844 37568839
37298958 37169050 36579123 35809147 35549193 35159248
35199310 35569331 36259318 36869325 37379358 37949288
38429248
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 232138
SPC MCD 232138
TXZ000-LAZ000-232345-
MESOSCALE DISCUSSION 2364
NWS STORM PREDICTION CENTER NORMAN OK
0338 PM CST MON DEC 23 2002
AREAS AFFECTED...SERN TX THRU CENTRAL LA
CONCERNING...TORNADO WATCH 799...

VALID 232138Z - 232345Z
SCATTERED TSTMS -- INCLUDING SEVERAL POSSIBLY TORNADIC SUPERCELLS
AND OTHERS WHICH MAY SOON BECOME SO -- ARE INDICATED MAINLY
BETWEEN I-45 AND I-49 ACROSS WW AREA. VERTICAL SHEAR AND
INSTABILITY PROFILES SUGGEST TORNADO THREAT WILL CONTINUE WITH
THIS ACTIVITY...AND ADDITIONAL SEVERE TSTMS ARE POSSIBLE OVER
REMAINDER WW AREA.

SURFACE ANALYSIS SHOWS ELONGATED AREA OF LOW PRESSURE ALONG
SURFACE FRONT -- BETWEEN HDO AND CLL. GIVEN STRONG PRESSURE
FALLS OVER EXTREME E TX AND LA...CYCLONE AND ASSOCIATED
ISALLOBARIC FORCING SHOULD CONSOLIDATE EWD WITH BACKED FLOW
CONTRIBUTING TO 0-3 KM SRH IN 300-500 J/KG RANGE. STRONGEST LOW
LEVEL SHEAR SHOULD REMAIN NEAR NWD-MOVING WARM FRONT WHICH IS
TAKING ON A DOUBLE STRUCTURE...SEE SPC MCD 2362 FOR MORE ANALYTIC
DETAILS. FORECAST SOUNDINGS INDICATE CAPPING REMAINS WEAK OVER
ALL BUT SWRN PORTION WW NEAR VCT...WHERE THREAT IS MORE
CONDITIONAL. HOWEVER...CONFLUENCE LINE NOW ANALYZED VERY NEAR
WRN EDGE OF WW MAY INDICATE CONVERGENCE SUFFICIENT TO INITIATE
MORE CONVECTION.


..EDWARDS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
29729733 30809733 31609470 32409207 31329207 30239207
29439470 28639733
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 232325
SPC MCD 232325
LAZ000-MSZ000-240230-
MESOSCALE DISCUSSION 2365
NWS STORM PREDICTION CENTER NORMAN OK
0525 PM CST MON DEC 23 2002
AREAS AFFECTED...SERN LA....SRN MS
CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 232325Z - 240230Z
STRONG THUNDERSTORMS ARE MOVING NEWD ACROSS SERN LA TOWARD SRN
MS. VERY STRONG LOW LEVEL SHEAR AND HELICITY SUGGEST
POTENTIAL FOR SUPERCELL DEVELOPMENT AND NEW TORNADO WATCH MAY BE
NEEDED WITHIN THE NEXT HOUR.

LATEST RADAR AND LIGHTNING DATA DEPICT A BAND OF INCREASING
THUNDERSTORM ACTIVITY MOVING NEWD ACROSS SERN LA. VAD WIND
PROFILE FROM LIX SHOWS VERY STRONG LOW LEVEL WINDS THAT VEER AND
INCREASE WITH HEIGHT...WITH 50 KT WINDS AROUND 1 KM AGL. TRENDS
OVER THE LAST 2 HOURS SHOW HELICITY IN THE LOWEST 1 KM INCREASING
TO MORE THAN 150 M2/S2...SUPPORTIVE OF TORNADIC SUPERCELLS.
ALTHOUGH ENVIRONMENT IS ONLY WEAKLY UNSTABLE ATTM WITH MUCAPE
AROUND 500 J/KG...DESTABILIZATION IS LIKELY TO OCCUR THIS EVENING
AS SOUTHERLY LOW LEVEL JET STRENGTHENS AND COASTAL WARM FRONT
MOVES INLAND. AREA WILL BE MONITORED FOR SUPERCELL DEVELOPMENT
AND A TORNADO WATCH MAY BE NEEDED WITHIN THE NEXT HOUR.

..WEISS.. 12/23/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
29559193 30369209 31349199 32239188 32339083 32128908
31678856 30598848 29088920
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240039
SPC MCD 240039
TXZ000-LAZ000-240245-
MESOSCALE DISCUSSION 2366
NWS STORM PREDICTION CENTER NORMAN OK
0639 PM CST MON DEC 23 2002
AREAS AFFECTED...SERN TX...WRN LA
CONCERNING...TORNADO WATCH 799...

VALID 240039Z - 240245Z
SHORT LINES OF STRONG/SEVERE THUNDERSTORMS CONTINUE TO DEVELOP
ALONG FRONTAL BOUNDARY EXTENDING FROM NRN LA WSWWD INTO CENTRAL
TX. AIR MASS SOUTH OF THE FRONT IN TX IS WARM/MOIST WITH SURFACE
TEMPERATURES IN THE LOW/MID 70S AND DEW POINTS IN THE UPPER
60S...WITH SLIGHTLY COOLER/DRIER CONDITIONS OVER CENTRAL LA. AIR
MASS IS MODERATELY UNSTABLE WITH SBCAPE OF 2000-3000 J/KG OVER TX
AND 1000-1500 J/KG OVER WRN LA. DEEP LAYER SHEAR IN THE LOWEST 6
KM REMAINS SUFFICIENT FOR SEVERE STORMS INCLUDING SUPERCELLS
ACROSS THE WATCH AREA...AND THREAT IS EXPECTED TO INCREASE
FURTHER THIS EVENING AS 90 KT MID LEVEL JET STREAK MOVES ENEWD
ACROSS CENTRAL TX.

UPSTREAM SEVERE STORMS SPREADING INTO CENTRAL TX ARE EXPECTED TO
CONTINUE MOVING ENEWD 40-50 KT...AND WILL APPROACH THE WRN EDGE
OF WW 799 AROUND 02Z. THUS...A NEW TORNADO WATCH WILL NEED TO BE
ISSUED ACROSS THIS GENERAL AREA OF TX AND LA PRIOR TO EXPIRATION
OF WW 799 AT 02Z.


..WEISS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
29729733 30809733 31609470 32409207 31329207 30239207
29439470 28639733
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240041
SPC MCD 240041
ILZ000-INZ000-KYZ000-240545-
MESOSCALE DISCUSSION 2367
NWS STORM PREDICTION CENTER NORMAN OK
0641 PM CST MON DEC 23 2002
AREAS AFFECTED...SRN IL...SRN IND...AND FAR NRN/NWRN KY
CONCERNING...PRECIPITATION TRENDS...WINTER PRECIPITATION

VALID 240041Z - 240545Z
A NARROW E-W ORIENTED BAND OF SNOW IS EXPECTED TO TRANSLATE EWD
FROM SERN MO/SRN IL ACROSS FAR SRN IND THIS EVENING AND INTO THE
OVERNIGHT PERIOD. A NARROW 15-25 NM WIDE ZONE OF 1 IN/HR SNOWFALL
RATES IS POSSIBLE IN ASSOCIATION WITH THIS FEATURE AS IT DEVELOPS
EWD...GENERALLY ALONG AND JUST TO THE NORTH OF THE OHIO RIVER.
DIAGNOSTIC FIELDS SUGGEST LARGE REGION OF PRECIPITATION ACROSS
LOWER MS RIVER VALLEY IS BEING DRIVEN PRIMARILY BY LOW-LEVEL WARM
ADVECTION/ISENTROPIC LIFT AND WILL MIGRATE NE AFFECTING
WRN/MIDDLE TN AND WRN/CENTRAL KY THROUGH 24/09Z. LOW-LEVEL
TEMPERATURES ARE GENERALLY TOO WARM IN THIS REGION FOR FROZEN
PRECIPITATION... HOWEVER...A MESOSCALE SNOW BAND IS EVIDENT AT
00Z ON MOSAIC RADAR IMAGERY AT THE NRN EDGE OF PRECIPITATION
SHIELD...EXTENDING FROM SGF TO MDH AND EWD ALONG THE LOWER OHIO
RIVER VALLEY. ON THE NRN FRINGE OF WARM ADVECTION

REGION...CONDITIONS WILL REMAIN FAVORABLE FOR BANDED
PRECIPITATION WITHIN FAVORED AREA OF FRONTOGENETIC FORCING AND
850-700MB DEFORMATION...WHICH MAY PROPAGATE SLOWLY NWD DURING THE
NEXT 6-9 HOURS...BUT REMAIN GENERALLY ACROSS SRN IL AND FAR SRN
IND. MODERATE SNOW HAS DEVELOPED ACROSS FAR SRN IL IN ASSOCIATION
WITH THIS FEATURE...AND OCCASIONAL HEAVY SNOW WITH RATES TO 1
IN/HR ARE POSSIBLE. AS LOW-LEVEL SATURATION TAKES

PLACE...DIABATIC COOLING SHOULD RESULT IN TEMPERATURES LOWERING
TO FREEZING OR COLDER ALONG AND NORTH OF THE OH RIVER. EARLY
MIXED PRECIPITATION SHOULD CHANGE TO SNOW ACROSS SRN IL AND SRN
IND THIS EVENING.


..BANACOS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
37929077 38228832 38418611 38558473
37658832 37588951 37879009 38169020 38609019 38579018
38768945 38898832 38958708 39038626 39028546 38588507
38088514 37958587 37818682 37688815
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240205
SPC MCD 240205
MSZ000-ALZ000-240400-
MESOSCALE DISCUSSION 2368
NWS STORM PREDICTION CENTER NORMAN OK
0805 PM CST MON DEC 23 2002
AREAS AFFECTED...SERN MS...SWRN AL
CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 240205Z - 240400Z
NEW WW MAY BE NEEDED SHORTLY ACROSS EXTREME SERN MS INTO SWRN AL.
RADAR SHOWS A SEVERE STORM MOVING ENEWD INTO EXTREME SERN MS THAT
HAS BEEN PRODUCING WIND DAMAGE. THIS CELLS HAS BEEN ASSOCIATED
WITH CYCLONIC ROTATION. VAD WIND PROFILES FROM LIX AND MOB
EXHIBIT WINDS INCREASING AND VEERING WITH HEIGHT...AND 50 KT FLOW
HAS BEEN STEADILY LOWERING IN ALTITUDE ON THE MOB PROFILE DURING
THE LAST TWO HOURS. THE KINEMATIC ENVIRONMENT IS CLEARLY
SUPPORTIVE OF TORNADIC SUPERCELLS...AND DESPITE THE MARGINAL
INSTABILITY ACROSS SERN MS/SWRN AL...SEVERE RISK APPEARS
SUFFICIENT TO WARRANT AN ADDITIONAL WATCH ACROSS THIS AREA.

..WEISS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
30208930 30808943 31468936 31778868 31918774 31608692
31108672 30468674 30108769
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240345
SPC MCD 240345
TXZ000-LAZ000-240545-
MESOSCALE DISCUSSION 2369
NWS STORM PREDICTION CENTER NORMAN OK
0945 PM CST MON DEC 23 2002
AREAS AFFECTED...SERN TX...WRN LA
CONCERNING...TORNADO WATCH 802...

VALID 240345Z - 240545Z
LINE OF SEVERE THUNDERSTORMS WITH EMBEDDED BOW SEGMENTS IS MOVING
EWD ACROSS SERN TX...WITH POTENTIAL FOR CELLS TO INCREASE AHEAD
OF THE LINE OVER WRN LA. SEVERE THREAT WILL CONTINUE NEXT
SEVERAL HOURS.

THE LINE OF STORMS IS MOVING EWD 45-50 KT AND WILL MOVE THROUGH
THE HOUSTON METRO AREA DURING THE NEXT HOUR. HGX RADIAL VELOCITY
DATA SHOW 50-60 KT INBOUND VELOCITY MOVING ACROSS PARTS OF HARRIS
AND FORT BEND COUNTIES...INDICATING POTENTIAL FOR DAMAGING WIND
GUSTS. IN ADDITION...HGX VAD PROFILE SHOWS STRONG LOW LEVEL
SHEAR SUGGESTING THREAT FOR EMBEDDED SMALL SCALE ROTATION AND
BRIEF TORNADOES ESPECIALLY ALONG NRN END OF BOW SEGMENTS.
FARTHER EAST...RADAR IS SHOWING CELLS SLOWLY INCREASING NEAR THE
SABINE RIVER. THESE CELLS ARE FORMING IN FAVORABLE ENVIRONMENT
WITH SBCAPE AROUND 2000 J/KG AND STRONG LOW LEVEL SHEAR AND
HELICITY...SUGGESTING POTENTIAL FOR INTENSIFICATION.

..WEISS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
28129667 30069553 31709427 32489199 29749198 28119667
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240444
SPC MCD 240444
LAZ000-MSZ000-ALZ000-240645-
MESOSCALE DISCUSSION 2370
NWS STORM PREDICTION CENTER NORMAN OK
1044 PM CST MON DEC 23 2002
AREAS AFFECTED...ERN/SERN LA...CENTRAL/SRN MS...SWRN AL
CONCERNING...TORNADO WATCH 801...803...

VALID 240444Z - 240645Z
WIND ENVIRONMENT REMAINS VERY FAVORABLE FOR SUPERCELL
THUNDERSTORMS ACROSS THE LOWER MS VALLEY REGION INTO THE EARLY
MORNING HOURS.

LATEST VAD PROFILES FROM LIX...MOB...AND JAN EXHIBIT LARGE
LOOPING HODOGRAPHS WITH WINDS VEERING AND INCREASING TO ABOVE 50
KT WITHIN 1 KM AGL. THESE ARE RESULTING IN STRONG LOW LEVEL
HELICITY AND SHEAR VALUES SUPPORTIVE OF TORNADIC SUPERCELLS
DESPITE MARGINAL INSTABILITY THROUGH MUCH OF THE REGION.
PERSISTENT ROTATING STORM IN WW 803 HAS MOVED FROM SERN MS INTO
WASHINGTON COUNTY AL TO THE NORTH OF THE SURFACE WARM FRONT THAT
EXTENDS FROM EXTREME SWRN AL INTO SERN LA NORTH OF LAKE
PONCHARTRAIN. THIS STORM MAY MAINTAIN TORNADIC POTENTIAL FOR
ANOTHER HOUR OR SO. HOWEVER...CURRENT ANALYSIS INDICATES STORM
IS MOVING INTO A LESS UNSTABLE ENVIRONMENT AND MAY BECOME
INCREASINGLY ELEVATED TO THE NORTH OF THE WARM FRONT...SUGGESTING
THAT THE SEVERE POTENTIAL MAY DIMINISH IN THE NEXT 1-2 HOURS.
OTHER WEAK CONVECTIVE CELLS CONTINUE TO DEVELOP OVER THE LOWER MS
VALLEY. ALTHOUGH THESE STORMS DO NOT APPEAR TO BE SEVERE AT THIS
TIME...THEY REMAIN EMBEDDED WITHIN AN ENVIRONMENT CHARACTERIZED
BY VERY STRONG SHEAR. THUS...THEY SHOULD BE MONITORED FOR SIGNS
OF STRENGTHENING AS DYNAMIC FORCING ASSOCIATED WITH THE UPPER
TROUGH OVER TX APPROACHES THE LOWER MS VALLEY DURING THE EARLY
MORNING HOURS. FARTHER WEST...A LINE OF SEVERE STORMS IS MOVING
EWD AT 45-55 KT AND LINEAR EXTRAPOLATION PLACES THIS LINE NEAR
THE WRN EDGE OF WW 801 BETWEEN 06-07Z.


..WEISS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
29709192 30859206 32369196 32669073 32768933 32178934
32008819 31978757 30238772
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240631
SPC MCD 240631
LAZ000-MSZ000-ALZ000-240800-
MESOSCALE DISCUSSION 2371
NWS STORM PREDICTION CENTER NORMAN OK
1231 AM CST TUE DEC 24 2002
AREAS AFFECTED...ERN LA/SRN MS/SWRN AL
CONCERNING...TORNADO WATCH 801...803...

VALID 240631Z - 240800Z
TORNADO THREAT INCREASING OVER THE LOWER MS VALLEY /ERN LA...SRN
MS AND SWRN AL/ WITHIN TORNADO WATCHES 801 AND 802.
REGIONAL RADARS SHOW SEVERAL STORMS OVER ERN/SERN LA INTO SRN MS/
SWRN AL WITH ROTATION COUPLETS. THESE STORMS ARE IN THE WARM
SECTOR WHERE THE AIR MASS IS VERY MOIST /SURFACE DEWPOINTS IN THE
UPPER 60S TO AROUND 70/...RESULTING IN LOW LCLS. WIND FIELDS ARE
VERY FAVORABLE IN THIS REGION WITH NEW/MOB SHOWING 0-1 KM SHEAR
AROUND 20 KT AND 0-2 KM SRH VALUES NEAR 300 M2/S2. THIS
ENVIRONMENT WILL CONTINUE TO SUPPORT THE POTENTIAL FOR STRONG
TORNADOES DURING THE NEXT SEVERAL HOURS AS THE UPPER THROUGH
MOVES THROUGH THE LOWER MS VALLEY.


..PETERS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
32389197 32789197 33229013 33478945 32558939 32238912
32108768 30288800 29968945 29129197
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240658
SPC MCD 240658
LAZ000-MSZ000-240830-
MESOSCALE DISCUSSION 2372
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CST TUE DEC 24 2002
AREAS AFFECTED...ERN AND SRN LA/SRN MS
CONCERNING...TORNADO WATCH 801...802...

VALID 240658Z - 240830Z
FAST MOVING LINE OF STRONG/SEVERE STORMS EXTENDING FROM NERN LA
INTO SWRN LA WILL CONTINUE EWD FOR THE NEXT SEVERAL HOURS INTO
SERN LA AND SRN MS WITH THE THREAT FOR DAMAGING WINDS AND
ISOLATED TORNADOES.

LATEST STORM TRACK INFORMATION SHOWS THIS LINE OF STORMS MOVING E
AT 45 KT. 06Z SPECIAL SOUNDINGS AT LCH /PRIOR TO STORMS/ AND LIX
SHOW A VERY UNSTABLE AIRMASS IN ADVANCE OF THE LINE OF STORMS
WITH MUCAPE VALUES RANGING FROM 2500-3000 J/KG. WATER VAPOR
IMAGERY INDICATES STRONG MID-UPPER LEVEL DRYING FROM SERN TX
INTO SRN LA... WHICH WILL CONTINUE TO AID IN THE FAST MOVEMENT OF
THIS LINE OF STORMS AS THEY MOVE EWD INTO A VERY UNSTABLE
AIRMASS.


..PETERS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
31879199 32159125 32079004 31029000 29599031 29299075
29189207 29279345 30579264
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240759
SPC MCD 240759
LAZ000-MSZ000-ALZ000-FLZ000-240900-
MESOSCALE DISCUSSION 2373
NWS STORM PREDICTION CENTER NORMAN OK
0159 AM CST TUE DEC 24 2002
AREAS AFFECTED...SERN LA/PORTIONS OF SRN MS AND SRN AL/WRN FL
PANHANDLE
CONCERNING...TORNADO WATCH 801...803...

VALID 240759Z - 240900Z
NEW WW WILL BE ISSUED WITHIN THE NEXT HOUR FOR SERN LA...PORTIONS
OF SRN MS AND SRN AL INTO THE WRN FL PANHANDLE.

REGIONAL RADARS SHOW A LINE OF STRONG/SEVERE STORMS EXTENDING
FROM FAR SWRN MS TO SOUTH CENTRAL LA WITH NUMEROUS
LINES/INDIVIDUAL STORMS WITHIN THE WARM SECTOR INTO SERN LA/SRN
MS AND SWRN AL. AIR MASS REMAINS FAVORABLE OVER THESE AREAS FOR
ORGANIZED STORMS/ SUPERCELLS PRODUCING DAMAGING WINDS AND
TORNADOES. WILL EXTEND NEW WATCH INTO PORTIONS OF SRN AL AND THE
WRN FL PANHANDLE AS UPPER TROUGH CONTINUES TO TRACK EWD.

..PETERS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
32179090 33019046 33358939 33098738 32528653 30478647
30008759 29178901 29129019 29299197
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 240815
SPC MCD 240815
MSZ000-ALZ000-FLZ000-241015-
MESOSCALE DISCUSSION 2374
NWS STORM PREDICTION CENTER NORMAN OK
0215 AM CST TUE DEC 24 2002
AREAS AFFECTED...SRN MS...SRN AL...WRN FL PANHANDLE
CONCERNING...SEVERE THUNDERSTORM POTENTIAL

VALID 240815Z - 241015Z
LATEST RADAR TRENDS INDICATE STORMS OVER SRN MS/AL ARE BECOMING
BETTER ORGANIZED...WITH THREAT OF TORNADOES INCREASING AS WELL.
SHEAR AND INSTABILITY PARAMETERS REMAIN EXTREMELY FAVORABLE FOR
TORNADIC SUPERCELLS. 06Z SOUNDINGS FROM LCH AND LIX INDICATE
2500-3000 J/KG MUCAPE...MUCH MORE THAN FORECAST BY THE MODELS.
LOW LEVEL STRUCTURE OF LIX SOUNDING...MODIFIED FOR LOW 70S OVER
LOW 70S AIR COMING OFF THE GULF...SHOW ZERO INHIBITION.
HOWEVER...RELATIVELY POOR LAPSE RATES FROM THE SURFACE TO 575 MB
HAVE RESULTED IN VERY SLOW INTENSIFICATION OVER THE PAST SEVERAL
HOURS. HOWEVER...LATEST RADAR TRENDS SHOW VILS
INCREASING...WHICH WOULD INDICATE LARGE INSTABILITY IS FINALLY
BEING REALIZED. TORNADIC SUPERCELL THREAT IS EXPECTED TO
INCREASE QUICKLY IN THIS AREA.


..JEWELL.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
31288694 30528693 30398795 30128938 31318950 31878839
31708717
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 241016
SPC MCD 241016
ALZ000-FLZ000-LAZ000-MSZ000-241145-
MESOSCALE DISCUSSION 2375
NWS STORM PREDICTION CENTER NORMAN OK
0416 AM CST TUE DEC 24 2002
AREAS AFFECTED...SERN LA/SERN MS/PORTIONS OF SRN AL/FAR WRN FL
PANHANDLE
CONCERNING...TORNADO WATCH 804...

VALID 241016Z - 241145Z
TORNADO AND DAMAGING WIND THREAT WILL CONTINUE FROM SERN LA/SERN
MS EWD INTO SRN AL AND THE WRN FL PANHANDLE FOR THE NEXT SEVERAL
HOURS.

LATEST SURFACE MESOANALYSIS SHOWS THE SURFACE LOW DEVELOPING EWD
OVER CENTRAL AL. A BROKEN LINE OF STRONG TO SEVERE STORMS
EXTENDING FROM SERN MS /CLARKE COUNTY/ SWWD TO SERN LA /ST. MARY
PARISH/ IS THE WRN BOUNDARY OF HIGHEST MOISTURE VALUES/STRONGEST
INSTABILITY. AS UPPER TROUGH CONTINUES TO PROGRESS EWD WITH
ASSOCIATED AREA OF MID-LEVEL DRY AIR MOVING OVER THE LOWER MS
VALLEY ATTM...STRONG TO SEVERE STORMS WILL PERSIST/DEVELOP AND
MOVE NEWD WITHIN THE WARM SECTOR. VAD WINDS SHOW LOW-MID LEVEL
SHEAR VALUES REMAIN FAVORABLE FOR TORNADIC DEVELOPMENT. WHILE...
MID- LEVEL DRY AIR INTRUSION WILL CONTINUE TO ENHANCE THE
DOWNDRAFT/DAMAGING WIND THREAT.


..PETERS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
29049105 30979021 31718916 32878722 32698594 30118665
29078743
NNNN
ZCZC SPCSWOMCD ALL
ACUS11 KWNS 241109
SPC MCD 241109
MSZ000-ALZ000-FLZ000-GAZ000-241245-
MESOSCALE DISCUSSION 2376
NWS STORM PREDICTION CENTER NORMAN OK
0509 AM CST TUE DEC 24 2002
AREAS AFFECTED...FAR SERN MS/SRN AL/WRN FL PANHANDLE/FAR SWRN GA
CONCERNING...TORNADO WATCH 804...

VALID 241109Z - 241245Z
NEW WW IS BEING ISSUED FOR SERN AL/WRN FL PANHANDLE/SWRN GA.
REGIONAL RADARS SHOW SEVERAL LINES OF STORMS MOVING EWD THROUGH
SRN AL AND FAR SERN MS INTO THE FAR WRN FL PANHANDLE. LATEST
SURFACE ANALYSIS PLACES THE SURFACE LOW OVER W CNTRL AL WITH A
WARM FRONT EXTENDING SEWD THROUGH THE WRN FL PANHANDLE AND A
SECOND WARM FRONT EXTENDING NEWD FROM THE LOW INTO NRN GA NEAR
ATL. WARM SECTOR CONTINUES TO MOVE EWD...ALTHOUGH IT HAS SLOWED
SOMEWHAT DURING THE LAST FEW HOURS. STRONGER SURFACE BASED
INSTABILITY LAGS THE LEAD LINE OF CONVECTION SUGGESTING THAT AN
EVENTUAL DECREASE IN STORM INTENSITY MAY DEVELOP LATER THIS
MORNING. UNTIL THEN...SURFACE DEWPOINTS HAVE INCREASED OVER SERN
AL/WRN FL PANHANDLE DURING THE LAST HOUR TO THE UPPER 50S TO
AROUND 60...INDICATING SEVERE THREAT WILL SPREAD E OF CURRENT WW
IN THE NEXT HOUR.


..PETERS.. 12/24/2002

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
32388611 32698544 32478379 30398392 29348430 29818624
30098777 29868951 30898869
NNNN