SPC AC 100559
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT SUN MAY 10 2015
VALID 111200Z - 121200Z
...THERE IS AN ENH RISK OF SVR TSTMS FROM THE MID-SOUTH TO THE LOWER
TN/OH VALLEYS...
...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE SLGT RISK AREA
AND EXTENDING NWD INTO SERN LOWER MI AND SWWD THROUGH THE LOWER MS
VALLEY TO MUCH OF ERN...CENTRAL AND SRN TX...
...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT RISK AREA
FROM NERN IL INTO CENTRAL LOWER MI TO THE LOWER GREAT LAKES AND SWD
TO THE SERN LA COAST TO CENTRAL AND SW TX...
...THERE IS A MRGL RISK OF SVR TSTMS ACROSS A SMALL PART OF NERN
NC...
...SUMMARY...
ISOLATED TO SCATTERED SEVERE STORMS WILL BE POSSIBLE MONDAY INTO
MONDAY EVENING ACROSS PORTIONS OF THE SOUTHERN GREAT LAKES REGION
AND THE OHIO AND TENNESSEE VALLEYS TO THE LOWER MISSISSIPPI VALLEY
AND THROUGH EAST...CENTRAL AND SOUTH TEXAS. STRONG TO SEVERE STORMS
MAY PERSIST THROUGH MONDAY NIGHT ACROSS SOUTH TEXAS.
...SRN GREAT LAKES...PORTIONS OF OH/TN VALLEYS AND NRN LOWER MS
VALLEY...
MOISTURE-CHANNEL IMAGERY SHOWED A CLOSED LOW CURRENTLY MOVING
THROUGH ERN CO AND FAR WRN KS. MODELS REMAIN CONSISTENT WITH THIS
CLOSED LOW WEAKENING DURING THE FIRST HALF OF MONDAY MOVING IT INTO
NRN MN. MEANWHILE...A COUPLE OF MIDLEVEL IMPULSES EMERGING FROM THE
CENTRAL ROCKIES SHOULD PHASE ACROSS NEB/KS MONDAY MORNING AND
AFTERNOON AND THEN ACCELERATE EWD THROUGH THE MIDWEST AND GREAT
LAKES. THIS WILL RESULT IN AMPLIFICATION OF THE CENTRAL/NRN U.S.
SHORTWAVE TROUGH...KEEPING IT PROGRESSIVE INTO THE GREAT LAKES AND
OH/TN VALLEYS...ACCOMPANIED BY STRENGTHENING DEEP-LAYER WLY WINDS
ACROSS THE OH VALLEY MONDAY NIGHT. THIS EVOLUTION WILL RESULT IN
STRONG HEIGHT FALLS SPREADING ACROSS THE GREAT LAKES/OH VALLEY
TOWARD THE CENTRAL APPALACHIANS DURING THE LATTER HALF OF THE
FORECAST PERIOD. AT THE SURFACE...A LOW WILL OCCLUDE FROM SRN MN
INTO THE UPPER GREAT LAKES...WHILE A SECONDARY LOW DEVELOPS OVER SRN
WI TRACKING INTO LOWER MI...AND EVENTUALLY REACHING SERN
ONTARIO/SWRN QUEBEC BY 12Z TUESDAY. A TRAILING COLD FRONT WILL
ADVANCE EWD ACROSS THE GREAT LAKES AND OH VALLEY REGION.
A BAND OF TSTMS SHOULD BE ONGOING AT 11/12Z FROM SRN MO THROUGH AR
INTO NERN TX ATTENDANT TO FORCING FOR ASCENT WITH A MIDLEVEL
SHORTWAVE TROUGH TRACKING NEWD FROM THE ERN PORTIONS OF THE SRN
PLAINS. NEW TSTM DEVELOPMENT WILL BE LIKELY ALONG THE NEWD TRACK OF
THIS SHORTWAVE TROUGH...WITH MODELS SUGGESTING SEVERAL N-S ORIENTED
BANDS OF STORMS MOVING FROM WEST-EAST ACROSS THIS PORTION OF THE
SLIGHT RISK AND ENH RISK AREAS. SURFACE HEATING IN ADVANCE OF THE
MORNING ACTIVITY/CLOUD COVER AND WITHIN A MOIST AIR MASS WILL
SUPPORT DESTABILIZATION. THE GREATEST LIKELIHOOD FOR SCATTERED
SEVERE STORMS ON MONDAY IS EXPECTED TO EXTEND FROM THE MID-SOUTH
/FAR ERN AR...NRN MS AND WRN TN/ NNEWD THROUGH SERN MO...AND THE
LOWER TN/OH VALLEYS...WHERE MODERATE INSTABILITY IS EXPECTED.
FARTHER NORTH INTO NWRN OH/NRN IND TO SERN LOWER MI...INSTABILITY
MAY BE MARGINAL...BUT CLOSER PROXIMITY TO STRONGER FORCING ALOFT MAY
COMPENSATE...MAINTAINING A SLIGHT RISK FOR SEVERE STORMS.
STRENGTHENING EFFECTIVE BULK SHEAR WITH SHEAR VECTORS ORIENTED
PARALLEL TO THE INITIATION BOUNDARIES SUGGESTS PRIMARILY
LINES/BOWING SEGMENTS WITH DAMAGING WINDS AND HAIL WILL BE THE
PRIMARY THREATS. HOWEVER...A TORNADO THREAT CANNOT BE RULED OUT
GIVEN ENHANCED LOW-LEVEL SHEAR IN VICINITY OF A 40-50 KT SWLY LLJ
EXTENDING FROM WRN TN TO LOWER MI. ALTHOUGH INSTABILITY WILL BE
WEAKENING INTO THE EVENING...A CONTINUED THREAT FOR DAMAGING WINDS
MAY PERSIST WITH EWD EXTENT ACROSS THE OH VALLEY REGION...AS
DEEP-LAYER WIND FIELDS VEER TO WLY AND STRENGTHEN WITH THE
APPROACHING AMPLIFIED SHORTWAVE TROUGH.
...LOWER MS VALLEY TO EASTERN...CENTRAL AND SOUTH TX...
FORCING FOR ASCENT IS EXPECTED TO BE WEAKER ALONG THE TRAILING
PORTION OF A COLD FRONT AS IT MOVES MORE SLOWLY SWD ACROSS THE LOWER
MS VALLEY AND INTO SOUTH TX. ALTHOUGH THIS REGION WILL BE REMOVED
FROM STRONGER FORCING AND HEIGHTS ARE EXPECTED TO RISE SOME THROUGH
MONDAY...THE AVAILABILITY OF STRONG INSTABILITY AND STRONG EFFECTIVE
BULK SHEAR SUPPORTS A THREAT FOR ORGANIZED SEVERE STORMS. THE
PRIMARY SOURCE FOR LIFT WILL BE THE SLOW-MOVING COLD FRONT AND GIVEN
HEIGHT RISES...THE OVERALL COVERAGE FOR STORMS MAY BE SOMEWHAT
LIMITED. THUS...THIS OUTLOOK WILL MAINTAIN A 15 PERCENT PROBABILITY
FOR SEVERE WEATHER. THERE IS THE POTENTIAL FOR ADDITIONAL STORMS TO
DEVELOP LATER MONDAY NIGHT INTO EARLY TUESDAY ACROSS SOUTH TX...AS
SLY LOW-LEVEL WINDS STRENGTHEN SOME WITH THE APPROACH OF A
SRN-STREAM IMPULSE INTO THIS REGION. RESIDUAL MODERATE INSTABILITY
AND STRONG BULK SHEAR SUGGEST SOME OF THESE STORMS COULD BE SEVERE.
...FAR NERN NC...
THE NEWD TRACK OF TROPICAL STORM ANA FROM ERN NC TO NEAR AND OFF THE
SRN DELMARVA REGION DURING MONDAY COMBINED WITH SOME
DESTABILIZATION IN THE ERN/NERN QUADRANT SUGGESTS AN ISOLATED
TORNADO THREAT. THIS THREAT SHOULD END BY MONDAY NIGHT AS THE
CENTER OF ANA MOVES OFFSHORE.
..PETERS.. 05/10/2015
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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