Severe weather US 2-2
Komende dinsdag is er een severe weather/tornado outbreak mogelijk in de VS. Nog veel onzekerheden qua details maar opvallend is dat er zelfs een day 7 15% severe warning was uitgegeven door het SPC. De parameters zien er indrukwekkend uit met mogelijk een EML in het zuidelijke aandachtsgebied waar de Cape waardes kunnen opbouwen en in de middag pre frontale discrete supercells kunnen ontstaan. Verschil in deze setting met voorgaande is dat de bovenlucht kouder is en de dauwpunten hoger wat een potentieel gevaarlijke situatie oplevert. Afwachten hoe dit zich gaat ontwikkelen...
Met minder dan een dag te gaan nog steeds veel onzekerheden. SPC heeft een enhanced risk uitstaan. Veel hangt af van de werkelijke CAPE waardes en de triggering van pre frontale cellen voor het koufront uit. Koude bovenluchten vallen toch enigzins tegen maar onderschatting van de modellen van de 2m temps kan de CAPE waardes hoger maken. Samen met de hoge shear een mogelijk gevaarlijke situatie.
NWS:
FOR TUESDAY THROUGH WEDNESDAY NIGHT...THINGS START TO COME TOGETHER ON TUESDAY. EXPECT MILD CONDITIONS WITH SOUTHWEST FLOW ALOFT TO CONTINUE UNTIL TUESDAY NIGHT A STRONG SHORTWAVE WILL PIVOT AROUND THE LONGWAVE UPPER TROUGH FROM THE CENTRAL PLAINS INTO THE MIDWEST, WITH THE ACCOMPANYING SURFACE LOW TRACKING THROUGH THE MISSOURI VALLEY TOWARD THE GREAT LAKES AND DRAGGING A COLD FRONT INTO THE AREA LATE TUESDAY INTO TUESDAY NIGHT. THE 12Z MODELS HAVE CONTINUED THE GENERAL TREND OF EXITING THE SEVERE WEATHER RISK OUT OF THE REGION BY AROUND MIDNIGHT..THEN HAVING SOME LINGERING CONVECTION AFTER 06Z WEDNESDAY MAINLY IN THE EASTERN AREAS. CONVECTIVE ALLOW GUIDANCE CONTINUES TO SHOW SUPERCELL STRUCTURES DEVELOPING AHEAD OF AN ADVANCING STRONG STORM LINE IN THE TUESDAY AFTERNOON-EVENING TIME FRAME AFTER THE MIDLEVEL CAP BREAKS DOWN. SOME OF THESE STRUCTURES MAY DEVELOP A FEW STRONG TORNADOES...ESP WHEN JET DYNAMICES INCREASES OVERHEAD DURING THE DAY. TORNADO PARAMETERS CONTINUE TO INDICATE THE POTENTIAL OF A FEW STRONG TORNADOES ACROSS A GOOD PORTION OF THE NORTH HALF OF THE REGION...
...LWR MS TO LWR-MID OH VLY TODAY/TNGT...
SIGNIFICANT SVR WEATHER...MAINLY IN THE FORM OF A COUPLE STRONG
TORNADOES...APPEARS POSSIBLE LATER TODAY THROUGH TNGT OVER PARTS OF
LWR MS...TN...AND LWR OH VLYS.
COMBINATION OF INCREASING LOW-LVL MOISTURE /WITH PW INCREASING TO
AOA 1.50 INCHES/ AND STRENGTHENING WIND FIELD /WITH 500 MB SW FLOW
AOA 75 KTS/ ATOP BROADENING WARM SECTOR ON SE SIDE OF KS UPR SYSTEM
WILL CREATE AN ENVIRONMENT FAVORABLE FOR SUSTAINED SUPERCELLS...AND
POTENTIALLY A FEW STRONG TORNADOES...LATER TODAY THROUGH EARLY WED.
MORNING RAOBS OVER THE LWR MS VLY...AND WELL-DEFINED...EWD-MOVING
BORE OVER SRN MO/AR...INDICATE PRESENCE OF STOUT CAP/INHIBITION
LAYER THAT LIKELY WILL DELAY ONSET OF SFC-BASED CONVECTION OVER MOST
OF WARM SECTOR TIL POSSIBLY MID TO LATE AFTN. BY THAT
TIME...HOWEVER...COMBINATION OF MODEST DAYTIME HEATING AND HEIGHT
FALLS CLOSE TO UPR TROUGH EXPECTED TO SUPPORT A BAND OR TWO
SFC-BASED TSTMS ALONG AND POSSIBLE JUST AHEAD OF COLD FRONT FROM S
CNTRL IL SSW INTO PARTS OF SE MO...FAR NE AR AND WRN TN.
LONG...HOOKED HODOGRAPHS...WITH CONSIDERABLE 0-1 SRH PROVIDED BY
SLIGHTLY BACKED NEAR-SFC FLOW...AND INCREASING MOISTURE /DEWPOINTS
INTO THE LOW TO MID 60S F/ SUGGEST POTENTIAL FOR SUPERCELLS WITH
LOW-LVL MESOCYCLONES AND TORNADOES...ESPECIALLY IN WRN KY...WRN
TN...AND NRN MS. THE STORMS LIKELY WILL EVOLVE INTO BROKEN LINE
SEGMENTS WITH A CONTINUING RISK FOR TORNADOES AND DMGG WIND FROM
EMBEDDED LEWPS THROUGH LATE EVE E/NE INTO MIDDLE TN AND CNTRL KY.
