|
|
|
|
Next update is scheduled by 01:00 UTC.
ACUS01 KWNS 191958
SWODY1
SPC AC 191956
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT SAT MAY 19 2012
VALID 192000Z - 201200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID MO VALLEY REGION
SSWWD INTO WRN OK/NWRN TX...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A SMALL PORTION OF S
FL...
...MID MO VALLEY REGION SSWWD INTO WRN OK/NWRN TX...
FORECAST REMAINS ON TRACK...WITH INITIAL STORM DEVELOPMENT FORECAST
INVOF THE SURFACE LOW NOW OVER CENTRAL KS...AHEAD OF WHICH THE
WARM-SECTOR AIRMASS HAS BECOME MODERATELY UNSTABLE. CONVECTION THUS
FAR HAS REMAINED TO THE COOL SIDE OF THE FRONT...BUT EXPECT THE CAP
TO CONTINUE TO WEAKEN OVER THE NEXT COUPLE OF HOURS FACILITATING
WARM SECTOR INITIATION.
GIVEN SHEAR SUPPORTIVE OF SUPERCELL STORMS...THREAT FOR LARGE HAIL
AND DAMAGING WINDS CAN BE EXPECTED AS THE STORMS INTENSIFY -- AND
EVENTUALLY DEVELOP SWD ACROSS OK. THREAT FOR A TORNADO OR TWO
SHOULD REMAIN GREATEST OVER S CENTRAL NEB/N CENTRAL KS NEAR THE
SURFACE LOW /JUST AHEAD OF THE MAIN UPPER CIRCULATION
CENTER/...WHERE MOST FAVORABLE LOW-LEVEL SHEAR SHOULD BE PRESENT.
STORMS SHOULD CONTINUE OVERNIGHT...THOUGH A SLOW WANE IN SEVERE
POTENTIAL IS EXPECTED WITH DIURNAL BOUNDARY LAYER STABILIZATION.
...S FL...
SHOWERS AND THUNDERSTORMS ARE ONGOING ACROSS MAINLY THE SRN HALF OF
FL THIS AFTERNOON...WITH STRONGEST STORM INITIATION OCCURRING IN
CONJUNCTION WITH THE E COAST SEA-BREEZE BOUNDARY MOVING WWD WITH
TIME. WITH SUFFICIENT CAPE TO FUEL THE CONVECTION AND FAIRLY STRONG
FLOW IN THE UPPER TROPOSPHERE...POTENTIAL FOR A FEW SEMI-ORGANIZED
STORMS CAPABLE OF PRODUCING BRIEF DAMAGING GUSTS AND MARGINAL HAIL
WILL CONTINUE FOR THE NEXT FEW HOURS.
..GOSS.. 05/19/2012
.PREV DISCUSSION... /ISSUED 1117 AM CDT SAT MAY 19 2012/
...CENTRAL/SRN PLAINS...
UPPER TROUGH OVER CO IS MOVING EWD TOWARD THE CENTRAL PLAINS AND
MODEL GUIDANCE INDICATES THIS FEATURE WILL BEGIN TO LIFT ENEWD
REACHING THE MIDDLE MO RIVER VALLEY LATER TONIGHT. THE TROUGH IS
ASSOCIATED WITH COLD MID LEVEL TEMPERATURES /-17C AT 500 MB/ WHICH
WILL SPREAD EWD INTO THE PLAINS THIS AFTERNOON AND EVENING. PRIMARY
SURFACE COLD FRONT EXTENDS FROM NWRN MN SSWWD ACROSS CENTRAL
NEB...WRN KS INTO THE NWRN TX PANHANDLE. THE FRONT WILL PROGRESS EWD
REACHING ERN NEB/CENTRAL KS/NWRN OK LATE THIS AFTERNOON/EVENING AND
PROVIDE A FOCUS FOR THUNDERSTORM DEVELOPMENT.
ALTHOUGH STRONG SOUTHERLY LOW LEVEL WINDS ARE CONTINUING FROM THE
SRN PLAINS INTO THE UPPER MS VALLEY...LOW LEVEL MOISTURE WILL BE
SLOW TO INCREASE SUBSTANTIALLY OWING TO PERSISTENT ANTICYCLONIC
TRAJECTORIES ACROSS THE WRN GULF OF MEXICO AND THE TX COAST. THIS
WILL LIMIT WARM SECTOR SURFACE DEW POINTS TO AROUND 60F OVER NEB AND
KS. HOWEVER...THE PRESENCE OF STEEP MID LEVEL LAPSE RATES
ASSOCIATED WITH AN ELEVATED MIXED LAYER OVER THE PLAINS WILL ENHANCE
POTENTIAL INSTABILITY WITH CAPE VALUES REACHING 1500-2000 J/KG LATER
THIS AFTERNOON AND EVENING. THE EML IS ALSO EXPECTED TO INHIBIT
DEVELOPMENT OF SURFACE-BASED STORMS UNTIL MID/LATE AFTERNOON ALONG
THE FRONT WHEN DIABATIC HEATING AND FOCUSED UPWARD MOTION WEAKEN THE
CAP SUFFICIENTLY FOR STORMS TO DEVELOP. CONSENSUS OF TRADITIONAL
AND CONVECTION-ALLOWING MODEL GUIDANCE PREDICTS CONVECTIVE
INITIATION FROM SOUTH CENTRAL NEB ACROSS CENTRAL KS INTO NWRN OK
DURING THE 21-23Z TIME FRAME.
AS THE UPPER TROUGH MOVES EWD...40-50 KT MID LEVEL SWLY FLOW WILL
OVERSPREAD THE FRONTAL REGION PROVIDING SUFFICIENT DEEP LAYER SHEAR
TO ENHANCE CONVECTIVE ORGANIZATION AND INTENSITY...INCLUDING
SUPERCELL STRUCTURES. THE STEEP LAPSE RATES WILL PROMOTE A THREAT
FOR VERY LARGE HAIL WITH STRONGER CELLS...WHILE THE WELL MIXED
BOUNDARY LAYER WILL ALSO FAVOR POTENTIAL FOR DAMAGING WIND GUSTS.
WITHIN SEVERAL HOURS AFTER INITIATION...THE STORMS ARE EXPECTED TO
DEVELOP INTO ONE OR MORE CONVECTIVE BANDS/LINES WITH ACTIVITY THEN
SPREADING EWD/NEWD WITH A GRADUAL TRANSITION INTO PRIMARILY A WIND
DAMAGE THREAT WITH TIME. ACTIVITY IS EXPECTED TO SLOWLY WEAKEN
AFTER 03Z AS DIURNAL STABILIZATION OCCURS AFTER SUNSET.
...SOUTH FL...
THE SYNOPTIC PATTERN AND THERMODYNAMIC ENVIRONMENT APPEAR SIMILAR TO
YESTERDAY WITH 12Z MFL SOUNDING SHOWING -10C AT 500 MB WITH
RESULTANT STEEPER LAPSE RATES ENHANCING INSTABILITY. ALTHOUGH LOW
LEVEL WINDS BELOW 700 MB REMAIN WEAK...A STRONG SUBTROPICAL JET IS
POSITIONED OVER SOUTH FL WITH 100 KT AT 200 MB. STRONG HEATING
NORTH OF THE CLOUD COVER OVER EXTREME SRN FL WILL PERMIT STORMS TO
DEVELOP WITHIN THE WEAKLY CAPPED ENVIRONMENT DURING THE EARLY/MID
AFTERNOON...WITH POTENTIAL FOR STRONGER CELLS TO PRODUCE LOCALIZED
DAMAGING WET MICROBURSTS AND MARGINALLY SEVERE HAIL.
...TN VLY/N GA AREA...
WRN EXTENSION OF LONG-LIVED...CAROLINAS UPPER TROUGH WILL MAINTAIN
CORRIDOR OF COOL MID LVL TEMPS /AOB -14 C AT 500 MB/ ATOP
STRONGLY-HEATED...RELATIVELY MOIST...VERY WEAKLY SHEARED ENVIRONMENT
OVER PARTS OF TN AND THE WRN SLOPES OF THE SRN APPALACHIANS. THIS
SETUP MAY YIELD DIURNAL PULSE STORMS WITH ISOLATED WET MICROBURSTS
AND/OR SVR HAIL.
|
|
|
|
|
contact
|
disclaimer
|
© 2006-2012 Lake County SKYWARN
Design & Hosting by Greg Perkins
|
