Saturday, December 21, 2013

MESO: Mesoscale Discussion 2095

ACUS11 KWNS 211220
SWOMCD
SPC MCD 211220
TXZ000-211415-

MESOSCALE DISCUSSION 2095
NWS STORM PREDICTION CENTER NORMAN OK
0620 AM CST SAT DEC 21 2013

AREAS AFFECTED...ERN PARTS OF THE EDWARDS PLATEAU AND TX HILL
COUNTRY TO NORTH CENTRAL TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 211220Z - 211415Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...SOME OF THE STRONGER ELEVATED STORMS ACROSS AND NNEWD FROM
THE TX HILL COUNTRY AND ERN PORTION OF THE EDWARDS PLATEAU MAY POSE
A THREAT FOR HAIL. MEANWHILE...IF STORMS CAN DEVELOP NEAR A
BOUNDARY THAT EXTENDS FROM 20 SW KCLL TO KBAZ TO KDRT...THEN THEY
WILL HAVE A POTENTIAL TO BE SURFACE BASED AND COULD POSE A THREAT
FOR DAMAGING WINDS AND/OR AN ISOLATED TORNADO. HOWEVER...THIS
POTENTIAL APPEARS TO BE LOW AT THIS TIME.

DISCUSSION...TRENDS IN REGIONAL RADAR IMAGERY/LIGHTNING DATA
INDICATED AN INCREASE IN TSTMS SINCE 10-1030Z FROM ERN PORTIONS OF
THE EDWARDS PLATEAU AND TX HILL COUNTRY NNEWD TO WRN PARTS OF NORTH
CENTRAL TX. TIME-LAPSE OF SATELLITE IMAGERY SUGGESTS THIS TSTM
ACTIVITY IS LOCATED ALONG THE LEADING EDGE OF DEEP LAYER ASCENT
ATTENDANT TO THE UPSTREAM VIGOROUS SHORTWAVE TROUGH CURRENTLY MOVING
INTO THE SRN HIGH PLAINS. THUS FAR...THE STORMS HAVE DEVELOPED AND
MOVED NEWD AT 50-60 KT...AND THIS SPEED SUGGESTS THE STORMS ARE
ELEVATED. MUCAPE 500 TO NEAR 1000 J/KG AND EFFECTIVE BULK SHEAR OF
40-50 KT ARE PRESENT ACROSS THIS REGION AND SUPPORTIVE OF ORGANIZED
STORMS....WITH THE STRONGER CORES POSING A THREAT FOR HAIL. AS
FORCING FOR ASCENT CONTINUES TO SPREAD ACROSS THE DISCUSSION
AREA...TSTMS WILL DEVELOP AND TRACK QUICKLY NEWD.

MEANWHILE...CURRENT TRENDS IN SATELLITE IMAGERY WOULD SUGGEST THAT
THE TRACK OF STRONGEST FORCING FOR ASCENT SHOULD REMAIN ON THE COOL
SIDE OF A BOUNDARY THAT AT 12Z EXTENDED ENEWD FROM KDRT TO KBAZ TO
20 SW KCLL. HOWEVER...IF A STORM CAN FORM INVOF THIS FRONT...STRONG
LOW LEVEL SHEAR AS NOTED ON AUSTIN/SAN ANTONIO WSR-88D AT 1154Z WITH
SFC-1 KM SHEAR OF 40 KT AND 0-1 KM SRH OF 400+ M2/S2 WOULD SUPPORT
AN ISOLATED TORNADO THREAT. CURRENT THINKING IS THAT THIS LATTER
SVR POTENTIAL SHOULD REMAIN LOW.

..PETERS/CORFIDI.. 12/21/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...HGX...FWD...EWX...SJT...

LAT...LON 29910001 30759978 31689967 32409903 33089802 33249752
33169667 32449661 31389676 30429692 30279718 29799814
29789953 29910001

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