May 27, 2015 1630 UTC Day 1 Convective Outlook
Updated: Wed May 27 16:23:38 UTC 2015 (20150527 1630Z Day 1 shapefile | 20150527 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20150527 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 34,027 262,945 Garden City, KS...Dodge City, KS...Liberal, KS...Pampa, TX...Guymon, OK...
SLIGHT 355,948 74,604,260 New York, NY...Philadelphia, PA...Dallas, TX...Detroit, MI...Indianapolis, IN...
MARGINAL 761,950 83,504,513 Houston, TX...San Antonio, TX...Austin, TX...Memphis, TN...Charlotte, NC...
Probabilistic Tornado Graphic
20150527 1630 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 % 25,701 201,041 Garden City, KS...Dodge City, KS...Liberal, KS...
2 % 146,503 10,360,175 Dallas, TX...Fort Worth, TX...Arlington, TX...Plano, TX...Garland, TX...
Probabilistic Damaging Wind Graphic
20150527 1630 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
15 % 348,001 73,526,139 New York, NY...Philadelphia, PA...Dallas, TX...Detroit, MI...Indianapolis, IN...
5 % 804,241 84,640,643 Houston, TX...San Antonio, TX...Austin, TX...Memphis, TN...Charlotte, NC...
Probabilistic Large Hail Graphic
20150527 1630 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 29,546 245,396 Garden City, KS...Dodge City, KS...Liberal, KS...Pampa, TX...Guymon, OK...
30 % 34,027 262,945 Garden City, KS...Dodge City, KS...Liberal, KS...Pampa, TX...Guymon, OK...
15 % 213,993 31,210,310 Dallas, TX...Detroit, MI...Indianapolis, IN...Columbus, OH...Fort Worth, TX...
5 % 557,799 42,946,797 Houston, TX...San Antonio, TX...Austin, TX...Memphis, TN...Oklahoma City, OK...
   SPC AC 271623

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1123 AM CDT WED MAY 27 2015

   VALID 271630Z - 281200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS OVER A PART OF THE CNTRL AND
   SRN HIGH PLAINS...

   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE ENH RISK OVER
   THE CNTRL/SRN PLAINS...

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE OH VALLEY
   AND LOWER GREAT LAKES...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF NEW ENGLAND INTO
   MID ATLANTIC...

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A SMALL PARTS OF THE LOWER
   MS VALLEY...

   ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE HIGH PLAINS TO
   ATLANTIC COAST...

   ...SUMMARY...
   SEVERE STORMS ARE PROBABLE THIS AFTERNOON INTO TONIGHT OVER THE
   CENTRAL AND SOUTHERN HIGH PLAINS.  ELSEWHERE...SEVERE STORMS ARE
   POSSIBLE THIS AFTERNOON INTO EVENING OVER PARTS OF THE NORTHERN MID
   ATLANTIC COAST REGION INTO NORTHERN NEW ENGLAND...THE UPPER OHIO
   VALLEY AND LOWER GREAT LAKES...AND THE LOWER MISSISSIPPI VALLEY.

   ...SYNOPSIS...

   A BROAD...CYCLONIC FLOW REGIME WILL BE MAINTAINED OVER THE CONUS
   THROUGH THE DAY ONE PERIOD WITH A NUMBER OF SHORT-WAVE TROUGHS
   EMBEDDED IN THIS UPPER-AIR PATTERN.  A MORE PROMINENT PERTURBATION
   OVER THE UPPER GREAT LAKES WILL DE-AMPLIFY WHILE TRANSLATING TOWARD
   THE NERN STATES.  THIS FEATURE WILL REMAIN LOOSELY PHASED WITH A
   COUPLE OF WEAKER IMPULSES WHICH WILL TRACK THROUGH THE OH VALLEY AND
   GULF COAST STATES.  FARTHER WEST...A SHORT-WAVE TROUGH WILL SLOWLY
   DRIFT SEWD THROUGH THE NRN INTER-MOUNTAIN REGION WHILE A WEAK
   DOWNSTREAM IMPULSE EJECTS NEWD INTO THE NRN/CNTRL HIGH PLAINS.

   AT THE SURFACE...A COLD FRONT ASSOCIATED WITH THE GREAT LAKES
   SHORT-WAVE TROUGH WILL CONTINUE EWD THROUGH THE LOWER GREAT LAKES
   WITH THE WRN EXTENSION OF THIS BOUNDARY LIFTING NWD THROUGH THE
   CNTRL INTO NRN PLAINS IN RESPONSE TO CYCLOGENESIS OVER THE NRN HIGH
   PLAINS.

   ...CNTRL HIGH PLAINS INTO OK/TX THIS AFTERNOON INTO TONIGHT...

   STRENGTHENING SLY LOW-LEVEL FLOW WILL INDUCE THE NWD FLUX OF AN
   INCREASINGLY MOIST BOUNDARY-LAYER FROM THE SRN INTO CNTRL HIGH
   PLAINS TODAY.  THIS PROCESS WILL OCCUR BENEATH A STEEP MID-LEVEL
   LAPSE RATE PLUME...YIELDING AFTERNOON MLCAPE RANGING FROM 1000-2000
   J/KG OVER ERN CO/KS TO 2500-3500+ J/KG OVER WRN PARTS OF OK/TX.

   WHILE SPECIFIC DETAILS REGARDING CONVECTIVE EVOLUTION STILL REMAIN
   SOMEWHAT UNCERTAIN...THE NWD-MOVING SYNOPTIC FRONT...HIGH PLAINS LEE
   TROUGH/DRYLINE...AND PRE-EXISTING OUTFLOW BOUNDARIES /NAMELY OVER OK
   AND TX/ WILL ALL BE POSSIBLE FOCI FOR STORM INITIATION THIS
   AFTERNOON.  SIMILAR TO TUESDAY...MID-LEVEL WINDS WILL NOT BE
   PARTICULARLY STRONG /I.E. 20-30 KT AT 500 MB/.  BUT...GIVEN THE
   SLY/SELY LOW-LEVEL FLOW REGIME...FORECAST HODOGRAPHS EXHIBIT
   CONSIDERABLE VEERING WITH HEIGHT WITH SUFFICIENT VERTICAL SHEAR TO
   SUPPORT SUPERCELL MORPHOLOGIES AS THE INITIAL STORM MODE.  LARGE
   HAIL WILL BE THE PRIMARY HAZARD...THOUGH A COUPLE OF TORNADOES ARE
   ALSO POSSIBLE.

   BY LATE EVENING INTO TONIGHT...STORMS MAY CONGEAL INTO ONE OR MORE
   MCSS WITH THE RISK FOR DAMAGING WINDS AND/OR HAIL SPREADING EWD/SEWD
   INTO LOWER ELEVATIONS OF THE PLAINS.

   ...NEW ENGLAND INTO THE MID ATLANTIC THIS AFTERNOON/EVENING...

   DESPITE THE PRESENCE OF POOR MID-LEVEL LAPSE RATES OBSERVED BY 12Z
   RAOBS...ABUNDANT BOUNDARY-LAYER MOISTURE AND DAYTIME HEATING WILL
   SUPPORT DESTABILIZATION OF THE WARM SECTOR WITH AFTERNOON MLCAPE
   VALUES APPROACHING 500-1500 J/KG.  WEAK HEIGHT FALLS ALOFT
   DOWNSTREAM FROM THE GREAT LAKES DISTURBANCE COUPLED WITH HEATING
   ALONG THE HIGHER TERRAIN OF THE NRN/CNTRL APPALACHIANS AND
   CONVERGENCE ALONG A PRE-FRONTAL CONFLUENCE ZONE/LEE TROUGH WILL
   FOSTER SCATTERED TSTMS BY AFTERNOON IN A GENERAL N-S BAND FROM
   UPSTATE NY INTO AT LEAST THE VA BLUE RIDGE.  THE STRONGEST VERTICAL
   SHEAR IN THE FORM OF A LARGELY WSWLY UNIDIRECTIONAL WIND PROFILE
   WILL RESIDE TO THE NORTH OF THE MASON-DIXON LINE WHERE UPSCALE
   GROWTH OF STORMS INTO CLUSTERS AND/OR LINE SEGMENTS APPEARS LIKELY. 
   DAMAGING OUTFLOW WINDS WILL BE THE PRIMARY HAZARD WITH THESE STORMS
   AS THEY SPREAD EWD INTO NEW ENGLAND AND TOWARD THE MID ATLANTIC
   COAST LATE THIS AFTERNOON INTO EVENING.

   ...OH VALLEY/LOWER GREAT LAKES THIS AFTERNOON/EVENING...

   VISIBLE SATELLITE AND MOSAIC RADAR DATA INDICATE A CONVECTIVELY
   INDUCED VORTICITY MAXIMUM PRESENT OVER SRN IL AS OF MID MORNING. 
   LOW-LEVEL UPLIFT ALONG THE SYNOPTIC COLD FRONT IN CONCERT WITH THE
   INFLUENCE OF THE MCV AND SHORT-WAVE TROUGH WILL GIVE RISE TO
   SCATTERED STORMS ACROSS THE REGION TODAY.  THE 12Z ILX SOUNDING
   SAMPLED A BELT OF 40-50 KT WSWLY WINDS IN THE 700-500-MB
   LAYER...WHICH WHEN COUPLED WITH A MOIST AND MODERATELY UNSTABLE
   THERMODYNAMIC ENVIRONMENT WILL SUPPORT THE POTENTIAL FOR BOWING LINE
   SEGMENTS AND AN ATTENDANT RISK FOR DAMAGING WIND GUSTS.

   ...LOWER MS VALLEY/CNTRL GULF STATES THIS AFTERNOON/EVENING...

   A LONG-LIVED MCS WHICH EVOLVED LAST NIGHT OVER TX IS IN A STATE OF
   DECAY OVER LA AS OF MID MORNING.  HOWEVER...THIS SYSTEM IS ATTENDED
   BY AN MCV AND FAIRLY SUBSTANTIAL COLD POOL WHICH SHOULD CONTINUE EWD
   ACROSS MS/AL TODAY...PROMOTING THE DEVELOPMENT OF NUMEROUS STORMS
   THIS AFTERNOON.  WHILE THE OVERALL KINEMATIC ENVIRONMENT WILL REMAIN
   SOMEWHAT MARGINAL FOR STORM ORGANIZATION...12Z REGIONAL RAOBS
   INDICATE THE POTENTIAL FOR STRONG INSTABILITY TO DEVELOP.  AND GIVEN
   THE HIGH-PW AIR MASS...CONSIDERABLE WATER-LOADING OF DOWNDRAFTS
   APPEARS POSSIBLE WITH A RISK FOR LOCALLY DAMAGING SURFACE WIND
   GUSTS.

   ..MEAD/MOSIER.. 05/27/2015

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z