SWODY1
SPC AC 161238
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0738 AM CDT FRI APR 16 2010
VALID 161300Z - 171200Z
...THERE IS A SLGT RISK OF SVR TSTMS TODAY ACROSS MUCH OF THE OHIO
VALLEY...
...SYNOPSIS...
AMPLIFIED RIDGING WITHIN A NORTHERN BRANCH OF THE PREVAILING SPLIT
UPPER FLOW MAY BECOME SUPPRESSED TODAY BY A COUPLE OF SHORT WAVE
IMPULSES PROGRESSING THROUGH ITS WESTERN AND NORTHERN
PERIPHERY...INCLUDING THE NORTHERN PORTION OF ONE SPLITTING AND
WEAKENING SYSTEM LIFTING INLAND ACROSS THE NORTH CENTRAL PACIFIC
COAST THROUGH THE NORTHERN INTERMOUNTAIN REGION. AT THE SAME
TIME...A SIGNIFICANT DOWNSTREAM CLOSED LOW/UPPER TROUGH...WHICH IS
ALREADY TURNING MORE SHARPLY SOUTHEASTWARD THROUGH THE UPPER
MISSISSIPPI VALLEY...APPEARS LIKELY TO CONTINUE DIGGING ACROSS THE
GREAT LAKES. MODELS INDICATE THAT THIS FEATURE WILL BE ACCOMPANIED
BY STRENGTHENING FLOW IN A BROAD CYCLONIC BELT ACROSS THE UPPER
MIDWEST AND OHIO VALLEY THROUGH THE MID ATLANTIC COAST.
ACROSS THE SOUTHERN TIER STATES...MID/UPPER FLOW WILL REMAIN
GENERALLY WEAK...WITH AN EMBEDDED CUT-OFF CIRCULATION ONLY VERY
SLOWLY SHIFTING EASTWARD ACROSS THE SOUTHERN PLAINS...TO THE SOUTH
OF THE UPPER RIDGE...AS THE SOUTHERN PORTION OF THE SPLITTING SHORT
WAVE TROUGH PROGRESSES ACROSS THE LOWER COLORADO VALLEY AND THROUGH
THE SOUTHERN PLATEAU REGION.
IN ASSOCIATION WITH THIS EVOLVING PATTERN...STEEP MID-LEVEL LAPSE
RATES ARE EXPECTED TO REMAIN CONFINED TO THE INTERMOUNTAIN WEST AND
SOUTHERN ROCKIES...WHERE FORCING WITH THE UPPER IMPULSES ...COUPLED
WITH FAVORABLE OROGRAPHY...WILL PROBABLY BE SUFFICIENT TO SUPPORT
SCATTERED THUNDERSTORM ACTIVITY. SUBSTANTIVE LOW-LEVEL MOISTURE
RETURN IS EXPECTED TO REMAIN CONFINED TO THE SOUTHERN PLAINS...WHERE
INHIBITION WILL REMAIN WEAK ENOUGH TO ALLOW CONSIDERABLE
THUNDERSTORM ACTIVITY. BUT...A WEAK RETURN FLOW OF MOISTURE IN
ADVANCE OF A COLD FRONT ASSOCIATED WITH THE DIGGING GREAT LAKES
UPPER TROUGH ALSO APPEARS LIKELY TO CONTRIBUTE TO SUFFICIENT
DESTABILIZATION FOR THUNDERSTORMS... ACROSS THE OHIO VALLEY INTO THE
LEE OF THE LOWER GREAT LAKES...AND THE NORTHERN MID ATLANTIC STATES.
...OHIO VALLEY...
SOUTH OF ONGOING WEAK FRONTAL/PRE-FRONTAL CONVECTION NOW DEVELOPING
EAST NORTHEASTWARD ACROSS SOUTHERN PORTIONS OF THE GREAT LAKES
REGION...BREAKS IN CLOUD COVER APPEAR SUFFICIENT TO ALLOW FOR
SUBSTANTIAL SURFACE HEATING AND STEEPENING OF LOW-LEVEL LAPSE RATES
THIS MORNING. AS SURFACE DEW POINTS CLIMB THROUGH THE
50S...GUIDANCE GENERALLY INDICATES THAT MIXED LAYER CAPE WILL EXCEED
500 J/KG BY 18Z...WITHIN A NARROW PRE-FRONTAL CORRIDOR. MODELS
SUGGEST THAT THIS DESTABILIZATION WILL LEAD TO A DEVELOPING LINE OR
LINES OF THUNDERSTORMS...NEARLY COINCIDENT WITH STRENGTHENING
LOWER/MID TROPOSPHERIC FLOW FIELDS...INCLUDING 50+ KT AT 700 MB
ACROSS PARTS OF INDIANA AND OHIO INTO WESTERN PENNSYLVANIA. WITH
LOW-LEVEL THERMODYNAMIC PROFILES CONDUCIVE TO DOWNWARD TRANSFER OF
THIS MOMENTUM...POTENTIALLY DAMAGING WIND GUSTS MAY ACCOMPANY
CONVECTION THIS AFTERNOON AS IT DEVELOPS EASTWARD AND SOUTHWARD
ACROSS THE MID/UPPER OHIO VALLEY...BEFORE WEAKENING AS INSTABILITY
WANES EARLY THIS EVENING.
..KERR/STOPPKOTTE.. 04/16/2010
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.
No comments:
Post a Comment