DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 250549
SWODY1
SPC AC 250547

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1247 AM CDT SAT AUG 25 2012

VALID 251200Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
AMPLIFICATION OF THE MID-LATITUDE WESTERLIES IS UNDERWAY ACROSS THE
PACIFIC...WITH A VIGOROUS CLOSED LOW NOW DIGGING ACROSS THE
NORTHEAST PACIFIC...TO THE EAST OF A BUILDING UPPER RIDGE. THE LOW
APPEARS LIKELY TO CONTINUE SOUTHEASTWARD TODAY INTO TONIGHT...BEFORE
GRADUALLY TURNING EASTWARD TOWARD NORTHERN PACIFIC COASTAL AREAS.
DOWNSTREAM...MID-LEVEL HEIGHT RISES ARE FORECAST FROM THE NORTHERN
ROCKIES INTO THE CANADIAN PRAIRIES...IN THE WAKE OF ANOTHER VIGOROUS
CLOSED LOW...WHICH APPEARS LIKELY TO SHIFT NORTHEAST OF SOUTHERN
SASKATCHEWAN TOWARD HUDSON BAY...ACCOMPANIED BY A SIGNIFICANT
SURFACE CYCLONE.

TO THE SOUTH OF THE INTERNATIONAL BORDER AREA...A LIGHT WESTERLY
MID/UPPER FLOW REGIME IS EXPECTED TO PERSIST ACROSS MUCH OF THE
U.S...WITH A WEAKENING CYCLONIC CIRCULATION/ELONGATING CYCLONIC
SHEAR AXIS SLOWLY SHIFTING ACROSS AND EAST OF THE CENTRAL PLAINS.
ANOTHER WEAK MID/UPPER CYCLONIC CIRCULATION MAY SLOWLY SHIFT
NORTHEASTWARD THROUGH THE MID ATLANTIC STATES...ON THE WESTERN
PERIPHERY OF THE ELONGATED ATLANTIC SUBTROPICAL RIDGE. BOTH OF
THESE FEATURES MAY CONTRIBUTE TO AREAS OF SCATTERED THUNDERSTORM
ACTIVITY TODAY.

SCATTERED THUNDERSTORM ACTIVITY ALSO APPEARS LIKELY AGAIN TODAY
ACROSS THE HIGHER TERRAIN OF THE GREAT BASIN AND SOUTHERN PLATEAU
...INTO THE CENTRAL AND SOUTHERN ROCKIES...AS WELL AS WITHIN A MOIST
ENVIRONMENT ACROSS PARTS OF THE WESTERN GULF COAST/LOWER MISSISSIPPI
AND TENNESSEE VALLEYS INTO THE SOUTHERN APPALACHIANS. A FEW
ADDITIONAL STORMS ARE ALSO POSSIBLE ALONG THE FRONT APPROACHING THE
UPPER GREAT LAKES REGION...AND ACROSS PARTS OF THE NORTHEAST.
HOWEVER...SEVERE WEATHER POTENTIAL ACROSS MOST AREAS APPEARS TO
REMAIN LOW TO NEGLIGIBLE.

...PARTS OF CENTRAL AND SOUTHERN PLAINS...
GUIDANCE INDICATES WEAKENING OF THE PLAINS SOUTHERLY LOW-LEVEL JET
TODAY...BUT IT DOES NOT APPEAR OUT OF THE QUESTION THAT A CORRIDOR
OF STRONGER SURFACE HEATING AND DEEPER BOUNDARY LAYER MIXING COULD
OCCUR ACROSS THE EASTERN TEXAS PANHANDLE AREA NORTHEASTWARD INTO
SOUTH CENTRAL KANSAS. GIVEN MODERATELY LARGE CAPE AND RELATIVELY
HIGH PRECIPITABLE WATER /1.75 TO 2 INCHES/ EXPECTED ACROSS THIS
REGION...HEAVY PRECIPITATION LOADING IN STORMS DEVELOPING ALONG AND
AHEAD OF THE MID-LEVEL CYCLONIC SHEAR AXIS...COUPLED WITH
EVAPORATIVE COOLING IN THE SUB-CLOUD LAYER...MAY CONTRIBUTE TO LOW
POTENTIAL FOR SEVERE SURFACE GUSTS LATE THIS AFTERNOON AND EVENING.

...SOUTHEAST FLORIDA COASTAL AREAS AND KEYS...
IT APPEARS POSSIBLE THAT LOW-LEVEL FLOW FIELDS AND VERTICAL SHEAR
MAY STRENGTHEN SUFFICIENTLY TO SUPPORT LOW TORNADO/SEVERE WIND
PROBABILITIES PRIOR TO 12Z SUNDAY...IN ADVANCE OF TROPICAL STORM
ISAAC...AS IT PROGRESSES WEST NORTHWESTWARD...TO THE NORTH OF CUBA.

..KERR/ROGERS.. 08/25/2012

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.