SPC AC 302003
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0303 PM CDT SUN JUL 30 2006
VALID 302000Z - 311200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER NRN PLAINS TO OH VALLEY...
...OH VALLEY...
AIR MASS ACROSS THE OH VALLEY EXPECTED TO RANGE FROM MODERATELY TO
VERY UNSTABLE INTO THE EARLY EVENING. RECENT TRENDS IN ONGOING MCS
OVER SRN GREAT LAKES REGION SUGGEST GREATER ESEWD MOVEMENT TO
CONTINUE AS INDICATED OVER SERN LOWER MI ATTM. SOME INTENSIFICATION
POSSIBLE IN THE WIND POTENTIAL WITH THE SYSTEM AS IT ENCOUNTERS
INCREASINGLY UNSTABLE AIR MASS OVER NRN/NERN OH WITH MCS POTENTIALLY
REACHING PARTS OF WRN PA/WRN NY BY EARLY EVENING. STORMS SHOULD
THEN WEAKEN AS THEY ENCOUNTER LESS FAVORABLE CONDITIONS AS AIR MASS
BEGINS TO STABILIZE WITH LOSS OF DAYTIME HEATING. ALTHOUGH THE SWRN
FLANK OF THE MCS IS MOVING MORE SLOWLY SWD THROUGH NRN IND/NRN IL
AND NERN IA...A VERY UNSTABLE AIR MASS ALONG/S OF THIS REGION AND
30-35 KT EFFECTIVE BULK SHEAR SUPPORTS A CONTINUED THREAT FOR SEVERE
STORMS INTO THE EVENING.
...NRN PLAINS EWD TO WRN GREAT LAKES...
SURFACE LOW WILL CONTINUE TO MOVE EWD ACROSS THE DAKOTAS THIS
FORECAST PERIOD...WHILE WARM FRONT CONTINUES TO LIFT NWD THROUGH ERN
ND/NRN MN. A VERY WARM TO HOT AND UNSTABLE AIR MASS /MLCAPE
EXCEEDING 4000 J/KG ACROSS MUCH OF MN/ HAS DEVELOPED IN THE WARM
SECTOR EAST OF THE SURFACE LOW. WARM SECTOR IS EXPECTED TO REMAIN
CAPPED THRU MUCH OF THE AFTERNOON AS INDICATED BY RECENT STRONG
CAPPING PER TAMDAR SOUNDINGS AT FAR/BJI. THUS...AFTERNOON/EVENING
SEVERE THREAT SHOULD BE LIMITED TO PARTS OF NERN MN/WRN U.P. OF MI
AS ELEVATED STORMS CONTINUE TO DEVELOP ON COOL SIDE OF CONVECTIVE
OUTFLOW WHERE SHEAR/CAPE VALUES REMAIN FAVORABLE FOR SOME SEVERE.
OVERNIGHT AS THE LOW LEVEL JET INCREASES TO 40-50 KT IN WARM SECTOR
AHEAD OF SURFACE LOW...SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP
VICINITY BOUNDARY IN ND EWD WITH POSSIBILITY FOR ONE OR MORE MCS/S
TRACKING EWD VICINITY THE INTERNATIONAL BORDER FROM ND TO LS.
DAMAGING WINDS WOULD LIKELY ACCOMPANY THE MCS/S GIVEN BOTH LARGE
AMOUNT OF INSTABILITY AND STEEP LAPSE RATES.
...NRN HIGH PLAINS...
UPPER SHORT WAVE TROUGH...NOW LOCATED OVER SRN BRITISH COLUMBIA/
PACIFIC NW...WILL TRACK NEWD OVER NRN ROCKIES REACHING SASKATCHEWAN
BY 12Z MONDAY. AS THIS OCCURS...60 METER HEIGHT FALLS ARE EXPECTED
INTO THE NRN PLAINS TONIGHT WITH RESULTANT EWD SHIFT OF RIDGE CREST
TOWARD THE WRN GREAT LAKES. ASCENT AHEAD OF THIS TROUGH SHOULD
SUPPORT AN INCREASING POTENTIAL FOR THUNDERSTORMS OVER THE HIGHER
TERRAIN OF CENTRAL MT AND/OR ALONG A COLD FRONT PROGRESSING EWD
ACROSS MT. 60 PLUS KT MID LEVEL WIND MAX ACCOMPANYING UPPER TROUGH
ACROSS MT THIS EVENING SUGGESTS SEVERE STORMS INCREASINGLY
LIKELY...MAINLY AS ACTIVITY MOVES EWD ENCOUNTERING GREATER
INSTABILITY CLOSER TO THE MT/ND BORDER THIS EVENING.
..PETERS.. 07/30/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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