Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 271255
SWODY1
SPC AC 271252

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT WED AUG 27 2014

VALID 271300Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN CO INTO THE CNTRL
PLNS...

...SUMMARY...
SCATTERED SEVERE STORMS WITH HAIL AND WIND ARE EXPECTED THIS
AFTERNOON FROM EASTERN COLORADO AND WESTERN KANSAS INTO SOUTHERN
NEBRASKA. ISOLATED WIND AND HAIL ALSO MAY OCCUR OVER MUCH OF
MISSOURI EASTWARD ACROSS THE OHIO VALLEY...WITH LOCALLY STRONG WIND
GUSTS OVER THE NORTHEASTERN STATES.

...SYNOPTIC SETUP...
SLOWLY-PROGRESSIVE SPLIT FLOW PATTERN WILL PREVAIL THROUGH THU. UT
CLOSED LOW WILL CONTINUE E INTO NW CO BY THIS EVE AND INTO NE CO
EARLY THU AS NRN STREAM IMPULSE NOW OVER THE UPR GRT LKS MOVES MORE
RAPIDLY E TO NEW BRUNSWICK. RIDGE WILL REMAIN STNRY FROM E TX TO THE
LWR OH VLY.

AT THE SFC...COLD FRONT NOW OVER THE ST LAWRENCE VLY/LWR GRT LKS
SHOULD ACCELERATE SEWD INTO THE MID-ATLANTIC STATES LATER TODAY/TNGT
AS GRT LKS TROUGH CONTINUES EWD. THE WRN PART OF THE SAME BOUNDARY
SHOULD ADVANCE NWD AS A WARM FRONT ACROSS THE CNTRL PLNS...WHILE THE
MIDDLE PORTION BECOMES STNRY OVER THE LWR OH VLY.

...ERN CO INTO CNTRL PLNS LATER TODAY/TNGT...
TSTM CLUSTERS ASSOCIATED WITH LEAD UPR IMPULSE NOW CROSSING THE
CNTRL HIGH PLNS SHOULD CONTINUE MAINLY ENE ACROSS PARTS OF NEB/NRN
KS. CLEARING IN WAKE OF THIS ACTIVITY AND...LATER IN THE
DAY...APPROACH OF UT/CO UPR SYSTEM...SHOULD FOSTER A NEW ROUND OF
STORMS INVOF LEE TROUGH AND WARM FRONT OVER ERN CO/WRN KS/SRN NEB.
STORMS ALSO SHOULD FORM ALONG THE CO FRONT RANGE.

COMBINATION OF INCREASING INSTABILITY/ASCENT WITH
STRENGTHENING/VERTICALLY-VEERING WIND PROFILES SHOULD YIELD A FEW
SUPERCELLS WITH SVR HAIL/WIND. A COUPLE TORNADOES ALSO MAY OCCUR
INVOF OUTFLOW BOUNDARY INTERSECTION IN NE CO AND IN NRN KS/SRN
NEB...WHERE LOW-LVL WINDS WILL REMAIN BACKED NEAR FRONT.
STORM MODE SHOULD...HOWEVER...FAIRLY QUICKLY BECOME FAIRLY MESSY AS
CONTINUED EWD ADVANCE OF UPR LOW PROMOTES ADDITIONAL STORM
DEVELOPMENT...ESPECIALLY OVER NE CO. THE RESULTING CLUSTERS SHOULD
MOVE/DEVELOP ENE ACROSS NRN KS AND NEB THROUGH THU MORNING ...WITH A
DIMINISHING RISK FOR SVR WIND/HAIL.

...MO EWD INTO THE LWR OH VLY THIS AFTN/EVE...
A BAND OF MODERATE INSTABILITY WILL PERSIST INVOF FRONT/CONVECTIVE
OUTFLOW BOUNDARIES FROM ERN KS AND MO EWD INTO THE OH VLY TODAY.
ASCENT AND FLOW ALOFT WILL...HOWEVER...REMAIN WEAK GIVEN PROXIMITY
OF UPR RIDGE. NEVERTHELESS...STRONG SFC HEATING...FAIRLY RICH
MOISTURE /PW AOA 1.75 INCHES/...AND LOW-LVL UPLIFT ALONG
FRONT-BOUNDARY SEGMENTS SUGGEST LIKELIHOOD FOR A FEW PULSE
STORMS/STORM CLUSTERS WITH LOCALLY DMGG WIND AND/OR SVR HAIL.

...NERN STATES THIS AFTN/EVE...
COLD FRONT AND PRE-FRONTAL TROUGH SHOULD SERVE TO FOCUS LOW-LVL
UPLIFT AHEAD OF GRT LKS UPR SYSTEM OVER PARTS OF PA...NY...AND SRN
NEW ENGLAND THIS AFTN AND EVE. SATELLITE SUGGESTS THAT THE UPR
SYSTEM MAY SOMEWHAT AMPLIFY LATER TODAY/TNGT AS IT PARTLY PHASES
WITH JET STREAK NOW ENTERING WRN ONT.

MOISTURE...BY AUGUST STANDARDS...WILL BE RELATIVELY MODEST...WITH PW
AROUND 1.50 INCHES. IN ADDITION...MID-LVL LAPSE RATES WILL BE FAIRLY
WEAK. BUT SFC HEATING SHOULD BE SUFFICIENT TO BOOST MUCAPE TO
1000-1500 J/KG IN A NARROW ZONE AHEAD OF FRONT. COUPLED WITH 20-25
KT WNWLY MID-LVL FLOW AND STRENGTHENING FORCING FOR ASCENT...SETUP
COULD YIELD A FEW STORMS CAPABLE OF LOCALLY DMGG GUSTS AND SMALL
HAIL...ESPECIALLY IN WRN/CNTRL PA. THE STORMS SHOULD WEAKEN QUICKLY
AFTER SUNSET.

..CORFIDI/ROGERS.. 08/27/2014



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