May 28, 2015 2000 UTC Day 1 Convective Outlook
Updated: Thu May 28 19:32:18 UTC 2015 (20150528 2000Z Day 1 shapefile | 20150528 2000Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150528 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 35,670 611,663 Abilene, TX...Midland, TX...San Angelo, TX...Big Spring, TX...Sweetwater, TX...
SLIGHT 321,327 32,544,075 New York, NY...Fort Worth, TX...Boston, MA...Oklahoma City, OK...Arlington, TX...
MARGINAL 628,266 52,015,560 Philadelphia, PA...San Antonio, TX...Dallas, TX...Austin, TX...Kansas City, MO...
Probabilistic Tornado Graphic
20150528 2000 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 81,787 1,340,819 Lubbock, TX...Abilene, TX...Midland, TX...Odessa, TX...San Angelo, TX...
2 % 265,197 16,567,983 San Antonio, TX...Dallas, TX...Austin, TX...Fort Worth, TX...Oklahoma City, OK...
Probabilistic Damaging Wind Graphic
20150528 2000 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
30 % 23,075 309,092 Abilene, TX...Big Spring, TX...Sweetwater, TX...Snyder, TX...Lamesa, TX...
15 % 333,628 34,122,147 New York, NY...Fort Worth, TX...Boston, MA...Oklahoma City, OK...Arlington, TX...
5 % 630,091 51,056,414 Philadelphia, PA...San Antonio, TX...Dallas, TX...Austin, TX...Kansas City, MO...
Probabilistic Large Hail Graphic
20150528 2000 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 79,256 1,407,327 Lubbock, TX...Abilene, TX...Midland, TX...Odessa, TX...San Angelo, TX...
30 % 35,592 611,711 Abilene, TX...Midland, TX...San Angelo, TX...Big Spring, TX...Sweetwater, TX...
15 % 256,454 8,449,170 Fort Worth, TX...Oklahoma City, OK...Arlington, TX...Wichita, KS...Lubbock, TX...
5 % 381,587 41,640,315 New York, NY...San Antonio, TX...Dallas, TX...Austin, TX...Boston, MA...
   SPC AC 281932

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0232 PM CDT THU MAY 28 2015

   VALID 282000Z - 291200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF WEST TX...

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND
   CNTRL PLAINS...

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NRN NJ...SE NY
   AND NEW ENGLAND...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE GREAT
   PLAINS...OZARKS...ARKLATEX...LOWER MS VALLEY AND CNTRL GULF COAST
   STATES...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF ERN
   PA...NJ...SE NY AND NEW ENGLAND...

   ...SUMMARY...
   SCATTERED SEVERE THUNDERSTORMS WITH LARGE HAIL...WIND DAMAGE...AND
   PERHAPS A TORNADO OR TWO WILL CONTINUE ACROSS PARTS OF THE SOUTHERN
   AND CENTRAL HIGH PLAINS THIS AFTERNOON INTO THIS EVENING. OTHER
   STRONG TO SEVERE THUNDERSTORMS ARE ONGOING ACROSS PARTS OF NEW
   ENGLAND THIS AFTERNOON WHERE STRONG WIND GUSTS WILL BE POSSIBLE.

   SEVERAL CHANGES HAVE BEEN MADE TO THE OUTLOOK FOR THIS ISSUANCE. THE
   FIRST CHANGE IS TO CONFINE THE 5 PERCENT TORNADO PROBABILITY TO
   AREAS OF WEST TX AND SE NM COVERED BY TORNADO WATCH 234. ALTHOUGH A
   TORNADO CAN NOT BE RULED OUT ACROSS WRN KS AND THE TX
   PANHANDLE...THIS THREAT SHOULD BE MARGINAL AND ASSOCIATED WITH
   NON-SUPERCELL TYPE STORMS. THE 2 PERCENT TORNADO PROBABILITY HAS
   BEEN EXPANDED SEWD ACROSS PARTS OF CNTRL AND SOUTH TX WHERE
   CONVECTION IS DEVELOPING IN A VERY MOIST AIRMASS. ANOTHER CHANGE TO
   THE OUTLOOK IS TO ADD A 30 PERCENT WIND DAMAGE PROBABILITY FROM NEAR
   LUBBOCK EWD ACROSS THE LOW ROLLING PLAINS. AN MCS IS ORGANIZING
   ACROSS WEST TX AND SHORT-TERM MODELS DEVELOP A BOWING LINE SEGMENT
   OVER THE NEXT FEW HOURS. THIS SCENARIO WOULD ENHANCE THE WIND DAMAGE
   POTENTIAL. ANOTHER CHANGE TO THE OUTLOOK IS TO REMOVE THE SLIGHT
   RISK AREA FROM PARTS OF VT...SE NY AND ERN PA WHERE THE AIRMASS IS
   DRYING BEHIND A COLD FRONT. THE FINAL CHANGE TO THE OUTLOOK IS TO
   REMOVE THE 2 PERCENT TORNADO PROBABILITY FROM NEW ENGLAND.

   ..BROYLES.. 05/28/2015

   .PREV DISCUSSION... /ISSUED 1133 AM CDT THU MAY 28 2015/

   ...SYNOPSIS...
   BROAD MID-LEVEL TROUGHING...COMPRISED OF SEVERAL SMALLER-SCALE
   CIRCULATIONS -- BOTH CONVECTIVE AND SYNOPTIC -- WILL CONTINUE
   SHIFTING ACROSS THE ROCKIES AND PLAINS STATES TODAY...WITH A
   SIMILARLY BROAD ZONE OF ENHANCED MID-LEVEL WLYS AFFECTING THE
   CENTRAL AND SRN ROCKIES/CENTRAL AND SRN PLAINS.  DOWNSTREAM...
   RIDGING WILL PREVAIL OVER MUCH OF THE E...WHILE STILL FARTHER
   DOWNSTREAM A VIGOROUS SHORT-WAVE TROUGH CROSSES SERN CANADA AND THE
   ADJACENT NERN CONUS.

   AT THE SURFACE...A COLD FRONT WILL CONTINUE SHIFTING EWD ACROSS THE
   NORTHEAST IN CONJUNCTION WITH THE AFOREMENTIONED SHORT-WAVE FEATURE.
    FARTHER W...A SURFACE TROUGH IS PROGGED TO SHIFT GRADUALLY EWD
   ACROSS WRN PORTIONS OF THE PLAINS...WITH SEVERAL BOUNDARIES/OUTFLOWS
   EVIDENT ACROSS THE WARM SECTOR FROM KS SWD TO TX.

   ...WRN PORTIONS OF THE CENTRAL AND SRN PLAINS...
   A VERY COMPLEX CONVECTIVE EVOLUTION IS EXPECTED OVER THE CENTRAL SRN
   PLAINS VICINITY TODAY...AS SEVERAL CLUSTERS OF ONGOING STORMS
   PERSIST ATTM...ALONG WITH WIDESPREAD CLOUD COVER AND SEVERAL 
   CONVECTIVE BOUNDARIES ARE EVIDENT ACROSS KS/OK/TX.  A LARGE
   CONVECTIVE SYSTEM CROSSING THE ERN OK VICINITY HAS TEMPORARILY
   STABILIZED THE AIRMASS OVER OK...BUT VERY STEEP LAPSE RATES ALOFT
   AND A MOIST BOUNDARY LAYER WILL COMBINE WITH DAYTIME HEATING TO
   RESULT IN POCKETS OF STRONGLY UNSTABLE AIR.  ONE PARTICULAR AREA OF
   ENHANCED DESTABILIZATION WILL OCCUR OVER PORTIONS OF THE WRN HALF OF
   TX...PARTICULARLY AWAY FROM ONGOING CLUSTERS OF CONVECTION.

   GIVEN THE POTENTIALLY VOLATILE AIRMASS LIKELY TO EVOLVE IN AREAS
   WHERE HEATING IS MAXIMIZED...THE KINEMATIC ENVIRONMENT -- FEATURING
   30 TO 35 KT MID-LEVEL WLYS SPREADING ATOP GENERALLY SELY
   BOUNDARY-LAYER WINDS -- WILL SUPPORT ROTATING/SUPERCELL STORMS. 
   ALONG WITH RISK FOR LOCALLY DAMAGING WINDS...VERY LARGE HAIL WILL BE
   POSSIBLE -- PARTICULARLY ACROSS PORTIONS OF THE WRN HALF OF TX.  A
   FEW TORNADOES WILL ALSO BE POSSIBLE -- PARTICULARLY IN
   VORTICITY-RICH AREAS NEAR AND N OF NWRN/WRN TX CONVECTIVE OUTFLOWS
   WHERE LOW-LEVEL FLOW IS MOST BACKED.

   WITH TIME...STORMS WILL LIKELY EVOLVE INTO ONE OR MORE LARGE
   MCS...WITH HEAVY RAIN POTENTIAL TO INCREASE ALONG WITH ONGOING
   SEVERE THREAT.

   SEVERE RISK WILL LIKELY REMAIN SOMEWHAT MORE ISOLATED NWD INTO NRN
   PORTIONS OF THE OUTLOOK AREA...WHERE A SLIGHTLY LESS
   UNSTABLE/SLIGHTLY LESS-SHEARED ENVIRONMENT IS EXPECTED. 
   STILL...STORMS DEVELOPING INVOF THE ADVANCING TROUGH MOVING OUT OF
   THE CENTRAL HIGH PLAINS WILL BE CAPABLE OF PRODUCING LARGE HAIL AND
   DAMAGING WINDS LOCALLY.

   ...NEW ENGLAND INTO SERN NY/NWRN PA/NRN NJ...
   THUNDERSTORMS HAVE BEGUN DEVELOPING FROM WRN AND CENTRAL ME SWWD
   INTO THE CHAMPLAIN VALLEY...AND WILL CONTINUE TO INCREASE IN
   COVERAGE THIS AFTERNOON ACROSS THE RISK AREA AHEAD OF AN ADVANCING
   COLD FRONT.  DESTABILIZATION OF A MOIST BOUNDARY LAYER ACROSS THE
   AREA HAS PUSHED MIXED-LAYER CAPE INTO THE 500 TO 1000 J/KG RANGE AT
   MIDDAY...WITH ADDITIONAL AFTERNOON HEATING/DESTABILIZATION TO
   SUPPORT THE ANTICIPATED CONVECTIVE INCREASE.  

   DEEP-LAYER FLOW REMAINS FAIRLY STRONG ACROSS THE AREA /40 TO 50 KT
   WSWLYS INDICATED AT MID LEVELS PER VWP AND RAOB DATA/ ON THE SRN
   SIDE OF THE SHORT-WAVE TROUGH SHIFTING NEWD ACROSS THE SRN QUEBEC
   VICINITY.  THIS WILL SUPPORT ORGANIZED CONVECTION -- MAINLY IN THE
   FORM OF LINEAR/BOWING SEGMENTS BUT ALSO WITH POTENTIAL FOR ROTATION
   IN STRONGER CELLS.  LOCALLY DAMAGING WINDS WILL ACCOMPANY STRONGER
   STORMS/LINE SEGMENTS AS CONVECTION SHIFTS EWD TOWARD THE NEW ENGLAND
   COAST -- IN CONJUNCTION WITH THE SURFACE FRONT -- LATER THIS
   AFTERNOON.

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z