SWODY2
SPC AC 271728
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT TUE MAR 27 2012
VALID 281200Z - 291200Z
...THERE IS A SLGT RISK OF SVR TSTMS WED AFTN AND EVE ACROSS PARTS
OF THE LWR OH/TN VALLEY INTO THE CNTRL APPALACHIANS...
...THERE IS A SLGT RISK OF SVR TSTMS WED AFTN AND EVE ACROSS PARTS
OF THE CNTRL PLAINS...
...SYNOPSIS...
MODELS INDICATE THAT A SHORT WAVE TROUGH WILL DIG FROM THE GREAT
LAKES REGION INTO LARGER-SCALE UPPER TROUGHING STILL EVOLVING ACROSS
EASTERN CANADA...MUCH OF THE NORTHEASTERN U.S. AND THE NORTHWESTERN
ATLANTIC DURING THIS PERIOD. AT THE SAME TIME...BROAD UPPER RIDGING
IS EXPECTED TO GENERALLY PREVAIL ACROSS MUCH OF THE REMAINDER OF THE
U.S...BUT A SIGNIFICANT SHORT WAVE IMPULSE EMERGING FROM A
DEAMPLIFYING UPPER TROUGH OFF THE PACIFIC COAST IS FORECAST TO
RAPIDLY LIFT INLAND ACROSS THE NORTHERN INTERMOUNTAIN REGION AND
NORTHERN ROCKIES BY LATE WEDNESDAY NIGHT.
A SURFACE FRONT ACCOMPANYING THE LEAD FEATURE IS EXPECTED TO
CONTINUE ITS SOUTHEASTWARD ADVANCE...FROM THE OHIO VALLEY INTO THE
MID ATLANTIC COAST AND TENNESSEE VALLEY...WHILE IT STALLS THEN
REDEVELOPS NORTHWARD THROUGH THE CENTRAL PLAINS...AHEAD OF THE COLD
FRONT WITH THE LATTER FEATURE...AS SURFACE TROUGHING DEEPENS ACROSS
THE HIGH PLAINS. PARTICULARLY EAST OF THE ROCKIES...THESE
BOUNDARIES APPEAR LIKELY TO PROVIDE A GENERAL FOCUS FOR THUNDERSTORM
ACTIVITY WEDNESDAY/WEDNESDAY NIGHT...SOME OF WHICH PROBABLY WILL
EXCEED SEVERE CRITERIA.
...LWR OH/TN VALLEYS INTO THE CNTRL APPALACHIANS...
THE SOUTHERN FRINGE OF THE STRONGER MID-LEVEL HEIGHT FALLS...
ASSOCIATED WITH THE SHORT WAVE TROUGH DIGGING OUT OF THE GREAT
LAKES...IS EXPECTED TO GRADUALLY OVERSPREAD THE REGION DURING THE
DAY WEDNESDAY...AHEAD OF THE SOUTHEASTWARD ADVANCING COLD FRONT.
COINCIDING WITH DAYTIME DESTABILIZATION WITHIN A MODESTLY MOIST WEST
SOUTHWESTERLY UPSLOPE LOW-LEVEL FLOW...AND FRONTAL
FORCING...GUIDANCE SUGGESTS POTENTIAL FOR THE EVOLUTION OF A FAIRLY
SUBSTANTIAL SQUALL LINE. INITIATION MAY OCCUR NEAR OR SOUTH OF THE
OHIO RIVER...ACROSS WEST VIRGINIA AND KENTUCKY...BY OR SHORTLY AFTER
18Z...BEFORE ADVANCING SOUTHWARD TOWARD THE UPPER TENNESSEE
VALLEY/CUMBERLAND PLATEAU AND CENTRAL APPALACHIANS THROUGH THE
REMAINDER OF THE AFTERNOON AND EVENING. IN THE PRESENCE OF AN
ENVIRONMENT CHARACTERIZED BY MODERATELY LARGE MIXED LAYER CAPE /ON
THE ORDER OF 1000-2000 J PER KG/ AND 30-40 KT WESTERLY DEEP LAYER
MEAN FLOW AND SHEAR...CONDITIONS SHOULD BE CONDUCIVE FOR DAMAGING
CONVECTIVELY GENERATED WIND GUSTS...AS WELL AS LARGE HAIL.
...CENTRAL PLAINS...
THE OUTLOOK IS MORE UNCERTAIN ACROSS THIS AREA...DUE TO THE
LIKELIHOOD OF SUBSTANTIAL...AND PERHAPS STRENGTHENING...MID-LEVEL
INHIBITION AND WEAK/UNCERTAIN FORCING FOR UPWARD VERTICAL MOTION.
HOWEVER...IN THE PRESENCE OF VERY STEEP MID-LEVEL LAPSE RATES...BOTH
CONDITIONAL AND CONVECTIVE INSTABILITY ARE EXPECTED TO BECOME QUITE
LARGE. MIXED LAYER CAPE MAY EXCEED 2000-3000 J/KG BY LATE AFTERNOON
ACROSS PARTS OF WESTERN OKLAHOMA INTO WESTERN AND CENTRAL KANSAS.
CONSIDERABLE VARIABILITY EXISTS... BUT SOME MODEL DATA...INCLUDING
HIGH RESOLUTION CONVECTION ALLOWING GUIDANCE...SUGGESTS POTENTIAL
FOR THE EVOLUTION OF A SMALL MESOSCALE CONVECTIVE SYSTEM IN RESPONSE
TO LOW/MID-LEVEL WARM ADVECTION ACROSS PARTS OF CENTRAL/EASTERN
KANSAS DURING THE MORNING HOURS. AT LEAST PARTIALLY DUE TO THE
APPARENT LACK OF A MORE SUBSTANTIVE SOUTHERLY LOW-LEVEL
JET...CONFIDENCE IN THIS DEVELOPMENT IS RELATIVELY LOW.
REGARDLESS...THE INITIATION OF ISOLATED TO WIDELY SCATTERED STORMS
STILL DOES NOT APPEAR OUT OF THE QUESTION IN THE PEAK AFTERNOON
HEATING ACROSS PARTS OF SOUTHWEST KANSAS INTO NORTHERN OKLAHOMA. IF
THIS OCCURS...ACTIVITY COULD BECOME ENHANCED BY A MORE SUBSTANTIVE
/30-40+ KT/ SOUTHERLY 850 MB JET...WHICH IS FORECAST TO DEVELOP
ACROSS THE HIGH PLAINS BY WEDNESDAY EVENING.
..KERR.. 03/27/2012
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.
No comments:
Post a Comment