000
ACUS11 KWNS 040324
SWOMCD
SPC MCD 040323
TXZ000-040830-

MESOSCALE DISCUSSION 0170
NWS STORM PREDICTION CENTER NORMAN OK
0923 PM CST MON MAR 03 2014

AREAS AFFECTED...S-CNTRL AND SE TX

CONCERNING...FREEZING RAIN

VALID 040323Z - 040830Z

SUMMARY...FREEZING RAIN THREAT WILL EXPAND SPATIALLY THROUGH LATE
EVENING AND EARLY TUE MORNING ACROSS S-CNTRL AND SE TX. RATES OF
0.05-0.1 INCH/HR WILL BE COMMON...WITH LOCALLY HIGHER AMOUNTS
POSSIBLE IN ASSOCIATION WITH THUNDERSTORMS.

DISCUSSION...SWATH OF CONVECTION EXTENDING FROM THE SRN HILL COUNTRY
EWD ALONG I-10 TO JUST W OF HOU APPEARS TO HAVE INITIATED IN
RESPONSE TO A WEAK UPPER IMPULSE OVER THE CENTRAL TX COAST /AS OF
03Z/...AND STRENGTHENING WAA REGIME ABOVE 2.5 KM AGL PRECEDING A
STRONGER VORT MAX APPROACHING THE BIG BEND. THIS IS OCCURRING MUCH
EARLIER THAN A MAJORITY OF 12Z/00Z MODEL GUIDANCE HAS
FORECAST...WITH EXCEPTION TO THE 12Z WRF-NSSL AND WRF-NMM
RUNS...WHICH APPEAR TO HAVE A SOMEWHAT REASONABLE DEPICTION OF
ONGOING ACTIVITY BUT ARE STILL SLOW WITH RESPECT TO OBSERVATIONS.

SFC OBS INDICATE TEMPERATURES ARE GENERALLY NEAR/ABOVE FREEZING
WHERE PRECIPITATION IS ONGOING CURRENTLY...WITH SFC FREEZING LINE
ANALYZED FROM NEAR TPL SEWD TO 20 N HOU AS OF 03Z. COMBINATION OF
WET-BULB COOLING /VIA ELEVATED CONVECTIVE PRECIPITATION FALLING INTO
RELATIVELY DRIER SUB-CLOUD LAYER/...AND MODEST LOW-LEVEL CAA OUT OF
THE N/NE...SHOULD RESULT IN TEMPERATURES FALLING BELOW FREEZING OVER
THE NEXT 2-3 HRS ACROSS THE REGION. THIS WILL OCCUR
CONTEMPORANEOUSLY WITH A CONTINUED INCREASE IN FORCING FOR ASCENT AS
THE AFOREMENTIONED SHORTWAVE IMPULSE MOVES OUT OF THE BIG BEND...AND
FACILITATES AN INCREASE IN PRECIPITATION COVERAGE OVER THE NEXT
SEVERAL HRS. OBSERVATIONAL TRENDS SUGGEST THE GREATEST THREAT FOR
FREEZING RAIN APPEARS TO BE FOCUSED NEAR/N OF THE I-10 CORRIDOR FROM
THE SRN HILL COUNTRY TOWARDS HOU.

..ROGERS.. 03/04/2014

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

ATTN...WFO...LCH...HGX...FWD...EWX...

LAT...LON   29709448 29579566 29579705 29739802 29929861 30399854
            30689786 30819750 30899668 30909601 30779531 30599468
            30439424 30149397 29869402 29709448