SPC AC 270635
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0135 AM CDT SUN APR 27 2008
VALID 291200Z - 301200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
SPEED MAX AND LOW-AMPLITUDE SHORTWAVE PERTURBATION - NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY INVOF MB-SASK BORDER -- IS EXPECTED TO
AMPLIFY CONSIDERABLY AND DIG SEWD THEN EWD THROUGH DAY-2 ACROSS OH
VALLEY AND CENTRAL APPALACHIANS. TROUGH SHOULD BECOME NEGATIVELY
TILTED BY 29/12Z...EJECTING NEWD OVER MID-ATLANTIC AND ERN NEW
ENGLAND DURING ENSUING 18 HOURS...AROUND SERN RIM OF ERN CANADIAN
UPPER CYCLONE. SFC COLD FRONT -- NOW CROSSING OK AND W TX -- IS
FCST TO EXPAND AND SWEEP SEWD ACROSS MOST OF ERN CONUS BY BEGINNING
OF PERIOD...EXITING S FL BETWEEN 29/12Z-29/18Z BASED ON CONSENSUS
OF SREF AND OPERATIONAL/DETERMINISTIC GUIDANCE PACKAGES. FROPA
SHOULD LEAVE CONUS E OF ROCKIES TOO STABLE AND/OR DRY FOR SVR RISK.
FARTHER W...LARGE MID-UPPER LEVEL CYCLONE CURRENTLY OVER GULF OF AK
IS FCST TO SHIFT SEWD TO PACIFIC NW AND CENTRAL/SRN BC. SEVERAL
SHORTWAVES WITH EMBEDDED/SMALLER-SCALE VORTICES SHOULD ORBIT COMMON
CENTER IN FUJIWHARA INTERACTION. AS THIS OCCURS...HEIGHT FALLS AND
LOW LEVEL WAA ARE FCST OVER NRN ROCKIES AND NRN HIGH PLAINS DURING
LATTER PART OF PERIOD. VERY WEAK MOISTURE AND STEEP LAPSE RATES MAY
SUPPORT SOME THUNDER OVER THIS AREA...AND COLD-CORE TSTMS ALSO MAY
OCCUR CLOSER TO COMPLEX UPPER LOW CENTER. HOWEVER...FCST LOW LEVEL
THETAE APPEARS TOO WEAK TO SUPPORT SVR THREAT.
..EDWARDS.. 04/27/2008
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1100Z
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