Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
ACUS01 KWNS 242001
SWODY1
SPC AC 242000

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT SUN JUL 24 2016

VALID 242000Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NORTHEAST IL...FAR
SOUTHEAST WI...SOUTHWEST MI AND NORTHERN INDIANA...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTHWEST PA REGION INTO
THE PANHANDLES OF WESTERN MD AND EASTERN WV...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL HIGH
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE GREAT LAKES REGION
THROUGH THE LOWER MO VALLEY INTO KS AND THE CENTRAL HIGH PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PORTIONS OF CENTRAL AND
WESTERN FL PENINSULA...

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND
LARGE HAIL WILL BE POSSIBLE OVER PARTS OF EASTERN COLORADO...AND
OVER PARTS OF NORTHEAST ILLINOIS...EXTREME SOUTHEAST
WISCONSIN...SOUTHWEST LOWER MICHIGAN AND NORTHERN INDIANA...MAINLY
DURING THE LATER AFTERNOON AND EVENING.  STRONG TO SEVERE STORMS
PRODUCING MAINLY A THREAT FOR DAMAGING WINDS WILL SPREAD ACROSS PART
OF THE NORTHERN WEST VIRGINIA PANHANDLE AND SOUTHWEST PENNSYLVANIA
TO THE PANHANDLES OF WESTERN MARYLAND AND EASTERN WEST VIRGINIA.
ISOLATED STRONG TO SEVERE STORMS REMAIN POSSIBLE ACROSS THE GREAT
LAKES AND MIDWEST REGIONS...AND OVER PARTS OF THE CENTRAL WESTERN
FLORIDA PENINSULA.

...SOUTHWEST PA INTO PANHANDLES OF WESTERN MD/EASTERN WV TO CENTRAL
OH...
MOSAIC RADAR IMAGERY SHOWED AN ONGOING ORGANIZED BAND OF STORMS
MOVING TO THE EAST/SOUTHEAST THROUGH WEST/SOUTHWEST PA WITH THIS
TREND EXPECTED TO PERSIST INTO THE EARLY EVENING ALONG A
NORTHWEST-SOUTHEAST ORIENTED INSTABILITY GRADIENT.  A MODERATELY
UNSTABLE WARM SECTOR HAS ADVANCED INTO PARTS OF WESTERN PA THIS
AFTERNOON WITH SEVERE-WEATHER THREAT EXTENDING INTO THE PANHANDLES
OF WESTERN MD AND EASTERN WV.  MEANWHILE...AN ISOLATED THREAT FOR
DAMAGING WINDS EXISTS IN CENTRAL OH WHERE DCAPE RANGES FROM
1000-1200 J/KG.

...CENTRAL HIGH PLAINS...
THE AIR MASS HAS BECOME MORE UNSTABLE FARTHER TO THE NORTH INTO
SOUTHEAST WY AND PART OF THE NEB PANHANDLE...THAN PREVIOUSLY
FORECAST.  GIVEN THIS FACTOR AND THE INCREASE IN BULK SHEAR ACROSS
THE CENTRAL HIGH PLAINS...THE SEVERE PROBABILITIES AND CATEGORICAL
RISK AREAS HAVE BEEN EXPANDED TO THE NORTH SOME.  FOR DETAILS
PERTAINING TO THE MESOSCALE AND SEVERE-WEATHER THREAT...PLEASE REFER
TO SPC MCD 1388.

..PETERS.. 07/24/2016

.PREV DISCUSSION... /ISSUED 1128 AM CDT SUN JUL 24 2016/

...NORTHEAST IL/EXTREME SERN WI/SWRN LOWER MI AND NRN INDIANA...
ONGOING STORMS OVER LOWER MI HAVE GENERATED A COMPOSITE OUTFLOW
BOUNDARY EXTENDING FROM NWRN OH AND NRN INDIANA INTO SRN LAKE MI.
WIDESPREAD CLOUD COVER TO THE NORTH OF THIS BOUNDARY IS EXPECTED TO
LIMIT DIABATIC HEATING AND STRENGTHEN THE THERMAL GRADIENT ALONG THE
COMPOSITE WARM FRONT/OUTFLOW BOUNDARY.  TO THE S/SW OF THIS
BOUNDARY...STRONG HEATING AND DIURNAL DESTABILIZATION WILL OCCUR
WITHIN AN ENVIRONMENT CHARACTERIZED BY AMPLE MOISTURE WITH SURFACE
DEW POINTS IN THE UPPER 70S...RESULTING IN MLCAPE OF 2500-4000 J/KG
LIKELY THIS AFTERNOON.

ALTHOUGH LARGE SCALE ASCENT ASSOCIATED WITH THE UPPER TROUGH
TRANSLATING EWD OVER NRN MN AND LAKE SUPERIOR WILL REMAIN NORTH OF
THIS AREA...WEAK LOW-LEVEL CONVERGENCE ALONG AN APPROACHING COLD
FRONT...POTENTIALLY ENHANCED NEAR A PROJECTED OUTFLOW BOUNDARY/FRONT
INTERSECTION...MAY BE SUFFICIENT TO INITIATE WIDELY SCATTERED
THUNDERSTORMS OVER THIS REGION DURING THE LATE AFTERNOON AND EVENING
HOURS.  MODEST VERTICAL SHEAR WILL PROMOTE A FEW ORGANIZED MULTICELL
CLUSTERS WITH POTENTIAL FOR DAMAGING WIND GUSTS AND LARGE HAIL TO
OCCUR.

...ERN CO...
MOIST UPSLOPE LOW-LEVEL FLOW WILL BECOME BETTER ESTABLISHED ACROSS
THE AREA THIS AFTERNOON AS STRONG HEATING OCCURS OVER THE MOUNTAINS
AND PLAINS...WITH SURFACE DEW POINTS REMAINING IN THE 50S ESPECIALLY
ACROSS THE PLAINS.  STEEP MID-LEVEL LAPSE RATES WILL CONTRIBUTE TO
MODERATE INSTABILITY WITH MLCAPE OF 1000-2000 J/KG DEVELOPING THIS
AFTERNOON.  MODEL CONSENSUS INDICATES STORMS WILL DEVELOP NEAR THE
FRONT RANGE BY MID-AFTERNOON WITH ACTIVITY SPREADING EWD ACROSS THE
PLAINS THROUGH THE EVENING.  STRONG DIRECTIONAL SHEAR WITH HEIGHT
WILL ENHANCE STORM ORGANIZATION WITH MORE INTENSE STORMS CAPABLE OF
PRODUCING LARGE HAIL AND STRONG WIND GUSTS.

...CENTRAL/SRN FL...
AS AN UPPER LOW MOVES WWD ACROSS THE SRN PENINSULA...THUNDERSTORMS
ARE EXPECTED TO CONTINUE DEVELOPING OVER THE CENTRAL/SRN PARTS OF
THE STATE.  RELATIVELY COOL MID-LEVEL TEMPERATURES ARE ENHANCING
LAPSE RATES WITH POTENTIAL FOR ISOLATED STRONG/SEVERE STORMS THIS
AFTERNOON AND EVENING.  SEE MCD 1385 FOR MORE DETAILED INFORMATION.

...PARTS OF NRN/ERN OH INTO WRN PA...
SATELLITE/RADAR ANIMATIONS SUGGEST PRESENCE OF AN MCV OVER NRN OH
THAT IS MOVING SLOWLY EWD.  A FEW STRONGER STORMS ARE ASSOCIATED
WITH THE MCV AT THIS TIME...AND CONVECTIVE DEVELOPMENT MAY BE
ENHANCED DOWNSTREAM FROM THE MCV INTO THIS EVENING.  FOR THIS
REASON...HAVE EXTENDED THE MARGINAL RISK AREA FARTHER E/SE ACROSS
ERN OH INTO WRN PA WHERE STORMS CAPABLE OF PRODUCING GUSTY WINDS AND
MARGINALLY SEVERE HAIL MAY OCCUR.

$$


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.