SWODY2
SPC AC 140536
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT MON JUL 14 2008
VALID 151200Z - 161200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
MODEST BRANCH OF THE WLYS WILL CONTINUE TO BE CONFINED TO THE NRN
TIER OF STATES ON TUESDAY. SEVERAL MID-LEVEL SHORTWAVE TROUGHS
EMBEDDED WITHIN THE FLOW WILL EXIST. ONE IMPULSE...LIKELY OVER THE
UPR GRTLKS REGION EARLY ON TUESDAY...WILL TRANSLATE INTO CNTRL
ONTARIO DURING THE DAY. ANOTHER UPSTREAM WAVE WILL ARRIVE OVER THE
NRN PLAINS STATES BY TUESDAY AFTN...THEN TO THE UPR GRTLKS REGION BY
12Z WEDNESDAY. TO THE S...AN EXPANSIVE SUB-TROPICAL RIDGE WILL
COVER THE SRN STATES...WITH A CENTER SHIFTING NWWD INTO THE SRN
ROCKIES.
...NRN PLAINS TO THE UPR GRTLKS REGION...
THOUGH MODEL GUIDANCE IS IN AGREEMENT WITH THE UPR LVL FLOW
REGIME...DIFFERENCES REMAIN ON THE LATITUDINAL PLACEMENT OF THE SFC
FRONT EXPECTED TO SETTLE SWD IN WAKE OF THE EARLY TUESDAY GRTLKS
IMPULSE. GIVEN STRONG RIDGE TO THE S...EXPECT THAT IT WILL STALL
AND LIE FROM UPR MI...NRN WI...CNTRL MN AND CNTRL SD BY TUESDAY
AFTN.
ELEVATED BANDS OF MORNING TSTMS WILL LIKELY ACCOMPANY ENHANCED WARM
ADVECTION REGIME TIED TO THE DEPARTING EARLY TUESDAY IMPULSE OVER
THE UPR/CNTRL GRTLKS REGION. ACTIVITY WILL TRANSLATE DOWNSTREAM
INTO ONTARIO AND WEAKEN DURING THE DAY. ATTENTION WILL THEN TURN TO
LOCATIONS FARTHER W INVOF THE FRONT.
LOW-LVL MOISTURE...CHARACTERIZED BY SFC DEW POINTS IN THE LWR-MID
60S...WILL BE TRANSPORTED NE FROM THE PLAINS AND BE AUGMENTED BY
EVAPOTRANSPIRATION BENEATH A STEEPENING ELEVATED MIXED LAYER ALONG/S
OF THE FRONT. THIS WILL CONTRIBUTE TO STRONG INSTABILITY BY TUESDAY
AFTN IN THE PRE-FRONTAL WARM SECTOR. BUT...FCST THERMODYNAMIC
PROFILES SUGGEST THAT THE MID-TROPOSPHERE WILL UNDERGO MODEST
WARMING THROUGH THE DAY...LIKELY CAPPING SFC-BASED PARCELS. GIVEN
LACK OF LARGER SCALE SUPPORT...HEATING AND SUSTAINED CONVERGENCE
INVOF THE FRONT WILL BE NEEDED TO INITIATE TSTMS. AT THIS
POINT...THERE ONLY APPEARS TO BE A LOW PROBABILITY OF THIS
OCCURRING. BUT...SHOULD A STORM DEVELOP...IT WOULD LIKELY BE
SUPERCELLULAR WITH LARGE HAIL THE PRIMARY THREAT.
MEANWHILE...ALONG THE TAIL-END OF THE FRONT ACROSS CNTRL/ERN SD...A
TRIPLE POINT WILL EVOLVE TUESDAY AFTN AS A WEAK SFC LOW EVOLVES WITH
AN ATTENDANT LEE-TROUGH EXTENDING SWWD INTO CNTRL NEB.
HERE...BOUNDARY LAYER TEMPERATURES WILL BE COMPARATIVELY HOTTER THAN
FARTHER NE. THUS...DESPITE EVEN STRONGER EML...ISOLD TSTMS MAY FORM
INVOF THE SFC LOW SWWD INTO PARTS OF CNTRL NEB BY LATE AFTN. THOUGH
THE REGION WILL BE FARTHER REMOVED FROM STRONGER WLYS LOCATED ACROSS
ND...VERY STEEP MID-LVL LAPSE RATES WILL BE SUFFICIENT FOR
HIGH-BASED SUPERCELLS WITH LARGE HAIL. ACTIVITY MAY MOVE NEWD INTO
THE BAROCLINIC ZONE OVERNIGHT INTO PARTS OF MN/WI WITH AN ISOLD
HAIL/WIND THREAT.
FINALLY...AS THE NEXT IMPULSE MOVES INTO THE NRN PLAINS EARLY
WEDNESDAY MORNING...LLJ WILL BACK AND INCREASE THROUGH THE
PLAINS...IMPINGING ON THE SFC-H85 FRONT OVER SD. INCREASING THETA-E
ADVECTION WILL CONTRIBUTE TO LATE NIGHT TSTMS DEVELOPING FROM SRN
ND/NRN-CNTRL SD. INCREASING MUCAPE/STEEP LAPSE RATES IN THE H7-H5
LAYER AND FAVORABLE EFFECTIVE SHEAR SUGGEST AT LEAST ISOLD SVR HAIL
MAY ACCOMPANY STRONGER STORMS.
..RACY.. 07/14/2008
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