SPC AC 141708
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1208 PM CDT FRI MAY 14 2004
VALID 151200Z - 161200Z
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 S WAL 25 ENE GSO
40 S SPA 50 W AGS 40 NNE MGR 35 SE VLD 30 S GNV MLB ...CONT... 20 S
LCH 15 SE GLH 30 SW CKV 35 SE SDF 20 SW UNI 20 S DUJ 10 SE SYR 30
NNE PBG.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 15 NE ELO 40 ENE BUB
45 ENE MCK 40 NW GCK 25 E DHT 10 WSW HOB 50 SW MRF.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 50 ESE DUG 25 NW TCS
20 E SAF 35 NW TAD 30 E DEN 55 ENE DGW 15 W 81V 45 W 4BQ 45 SE BIL
50 NW PIH 40 W OWY 80 WNW WMC 45 WNW SVE 35 SSE MHS 20 WNW MHS 35
ENE EUG 25 ENE BLI.
...NO SVR TSTM AREAS FORECAST...
...NORTHERN PLAINS/HIGH PLAINS...
SFC ANALYSIS SHOWS DRY BOUNDARY LAYER AIR CURRENTLY IN PLACE ACROSS
THE REGION. HOWEVER...A DEVELOPING LOW-LEVEL JET TONIGHT WILL
TRANSPORT LOW-LEVEL MOISTURE FROM THE CNTRL PLAINS NWD. SFC
DEWPOINTS SHOULD REACH THE 40S F ACROSS MT...SD AND ND BY AFTERNOON
WITH SOME 50 F DEWPOINTS POSSIBLE. SFC TEMPS ARE FORECAST TO REACH
65 TO 70 F SATURDAY AFTERNOON AND THIS COUPLED WITH THE RELATIVELY
DRY BOUNDARY LAYER AIR SHOULD KEEP MLCAPE VALUES BELOW 500 J/KG.
THIS WILL BE A LIMITING FACTOR FOR SEVERE STORMS.
AT UPPER-LEVELS...A BROAD NRN US TROUGH WILL MOVE EWD ACROSS THE NRN
PLAINS DURING THE DAY. THE MODELS ARE IN GENERAL
AGREEMENT...SPREADING A BAND OF LARGE-SCALE ASCENT FROM WEST TO EAST
ACROSS THE DAKOTAS IN THE AFTERNOON. THE LIFT COMBINED WITH
CONVERGENCE ALONG A SFC TROUGH IN THE DAKOTAS MAY BE SUFFICIENT FOR
SCATTERED STORM INITIATION. OTHER STORMS WILL LIKELY DEVELOP IN THE
NRN ROCKIES DUE TO SFC HEATING AND TOPOGRAPHIC FORCING. THIS
CONVECTION WILL SPREAD EWD INTO THE HIGH PLAINS DURING THE
AFTERNOON.
FORECAST SOUNDINGS SUGGEST THAT MODERATE DEEP LAYER SHEAR WILL EXIST
ACROSS THE ENTIRE HIGH PLAINS AND NORTHERN PLAINS REGION. THIS
SUGGESTS THAT SUPERCELLS WILL BE POSSIBLE ESPECIALLY WHERE MOISTURE
AND INSTABILITY IS LOCALLY MAXIMIZED. TEMPS SHOULD BE COLD ALOFT
(500 MB TEMPS AROUND -20C) AND THIS WILL FAVOR A HAIL POTENTIAL. THE
WINDOW FOR SEVERE SHOULD BE NARROW AND FOCUSED NEAR PEAK HEATING DUE
TO THE MINIMAL AMOUNT OF INSTABILITY. ALTHOUGH WARMER MID-LEVEL
TEMPS WILL EXIST ACROSS CO AND WY...THIS CONVECTION WILL ALSO HAVE A
HAIL POTENTIAL MAINLY BEFORE DARK.
...MID-ATLANTIC AND NEW ENGLAND STATES...
A WELL-DEFINED MOIST AXIS IS CURRENTLY IN PLACE FROM ERN VA
EXTENDING NWD TO SCNTRL NY WHERE SFC DEWPOINTS RANGE FROM 65 TO 70
F. THIS AXIS WILL REMAIN IN PLACE THROUGH SATURDAY AND WARMING SFC
TEMPS SHOULD RESULT IN MODERATE INSTABILITY BY AFTERNOON.
A COLD FRONT CURRENTLY OVER SRN ONTARIO WILL CONTINUE TO MOVE SEWD
TONIGHT AND SHOULD REACH COASTAL AREAS OF THE MID-ATLANTIC STATES
AND NEW ENGLAND STATES BY LATE AFTERNOON. ALTHOUGH LARGE-SCALE
ASCENT WILL BE WEAK...STRONG LOW-LEVEL CONVERGENCE ALONG THE FRONTAL
AXIS AND THE MODERATE INSTABILITY WILL PROVIDE ENOUGH LIFT FOR
ISOLATED THUNDERSTORMS.
AT THE MID-LEVELS...A BROAD UNITED STATES TROUGH WILL MOVE EWD INTO
THE UPPER MIDWEST AND GREAT LAKES STATES. HOWEVER...THE STRONGEST
MID-LEVEL FLOW WILL REMAIN ACROSS THE APPALACHIAN MTNS SATURDAY.
FORECAST SOUNDINGS SHOW LESS THAN 30 KT OF 0-6 KM SHEAR. THIS WILL
BE PROBLEMATIC FOR STORM ORGANIZATION AND WILL FAVOR A MULTICELL
MODE OF CONVECTION. FORECAST SOUNDINGS SHOW STEEP LOW-LEVEL LAPSE
RATES AND THIS COMBINED WITH THE MODERATE INSTABILITY WILL BE ENOUGH
FOR A FEW DAMAGING WIND GUSTS. DUE TO THE WEAK FORCING
ALOFT...COVERAGE SHOULD REMAIN ISOLATED AND THE STORMS SHOULD DIE
QUICKLY AFTER DARK.
..BROYLES.. 05/14/2004
...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3. THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED FOR 0800Z
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