Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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000
FXUS64 KHGX 220336
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
936 PM CST FRI NOV 21 2014

.DISCUSSION...
NO CHANGES TO THIS UPDATE. THE BEST WARM AIR AND MOISTURE
ADVECTION WAS TO THE WEST OF THE FORECAST AREA...GENERALLY ACROSS
THE CENTRAL PART OF THE STATE. THE 00Z NAM12 AND THE HRRR BOTH
KEEP ISOLATED TO SCATTERED RAIN CHANCES OVER THE FAR WESTERN
COUNTIES THROUGH ABOUT 3 AM. CHANCES RETURN BY LATE MORNING ON
SATURDAY.

THE MAIN EVENT STILL LOOKS TO OCCUR SATURDAY AFTERNOON AND
EVENING. THE 00Z NAM12 AND HRRR ARE A BIT SLOWER THAN THE 18Z
TEXAS TECH WRF. THE NAM12 AND HRRR PUSH AN INITIAL LINE OF STORMS
INTO SE TX DURING THE LATE AFTERNOON TO EARLY EVENING TIME PERIOD.
A SQUALL LINE THEN DEVELOPS AND MOVES OVERHEAD LATE EVENING INTO
THE OVERNIGHT PERIOD SATURDAY NIGHT. THE TEXAS TECH WRF IS ABOUT 3
HOURS OR SO QUICKER WITH THE TIMING. AFTER LOOKING OVER THE 00Z
NAMBUFR MODEL SOUNDINGS...THE CURRENT THINKING IS STILL IN LINE
WITH THE PREVIOUS REGARDING THE SEVERE THREAT -- A SLIGHT RISK
FOR SEVERE STORMS WITH DAMAGING WINDS AND HAIL THE MAIN THREATS
AND ISOLATED TORNADOES POSSIBLE.

40

&&

.PREV DISCUSSION... /ISSUED 554 PM CST FRI NOV 21 2014/

DISCUSSION...
00Z TAF DISCUSSION IN AVIATION SECTION.

AVIATION...
COMPLICATED FORECAST FOR AVIATION CONCERNS THE NEXT 24-30HRS.
CIGS TONIGHT SHOULD MOSTLY BE MVFR FOR SE TX TERMINALS. THERE IS
SOME VFR CIGS ALONG THE COAST BUT THOSE SHOULD FILL BACK IN AT
MVFR LEVELS. ONLY QUESTION WILL BE IFR CIGS WHICH LOOK MORE
POSSIBLE OVER KCLL/KUTS/KCXO BUT COULD EASILY DEVELOP OVER THE
HOUSTON AREA IN THE MORNING. MAY NEED TO ADD A TEMPO GROUP FOR IFR
WITH 06Z TAFS SHOULD THERE BE MORE CONFIDENCE IN IFR DEVELOPING.
MVFR CIGS SHOULD REMAIN AND MAY BECOME VFR IN THE AFTERNOON BUT
NOT AS LIKELY. WILL STICK WITH NAM/GFS SOLUTIONS FOR CONVECTIVE
TRENDS AT THIS MOMENT. UPPER LOW OVER AZ SHOULD BE OVER RIO GRANDE
VALLEY NEAR DRT BY 00Z SUN. LEAD SHORTWAVE SHOULD MOVE OVER SE TX
BY THIS TIME OR END OF CURRENT TAF. WAVE MAY INITIATE ONE ROUND OF
TSRA FOR THE AREA. MAIN UPPER LOW THEN MOVES TO ACT/AUS BY 06Z BY
WHICH A 2ND ROUND OF CONVECTION MAY AFFECT THE AREA. ADDED PROB30
GROUP FOR IAH TO ACCOUNT FOR THIS TIMING. OBVIOUSLY TAFS WILL
UNDERGO SEVERAL CHANGES AS THIS SYSTEM EVOLVES BUT THE MAIN
HIGHLIGHT IS TO EXPECT CONVECTION TOMORROW AFTERNOON AND NIGHT TO
DISRUPT AIRPORT OPERATIONS.

39

PREV DISCUSSION... /ISSUED 344 PM CST FRI NOV 21 2014/

DISCUSSION...
SCATTERED LIGHT SHOWERS CONTINUE ACROSS THE REGION THIS AFTERNOON.
GREATEST COVERAGE AND AMOUNTS HAVE BEEN ACROSS OUR WESTERN
COUNTIES THIS AFTERNOON WHERE SOME LOCATIONS HAVE RECEIVED OVER AN
INCH OF RAIN SINCE EARLY THIS MORNING. HAVE SEEN SOME LIGHTNING
WITH THE ACTIVITY JUST OFF TO OUR WEST BUT BEST CHANCES FOR
THUNDER THIS EVENING SHOULD REMAIN BACK ACROSS THE HILL COUNTRY
WHERE THE LOW LEVEL JET WILL SET UP FOR THE NIGHT.

SATURDAY STILL LOOKING TO BE QUITE ACTIVE AS AN UPPER LEVEL STORM
SYSTEM APPROACHES THE REGION. THIS SYSTEM...CURRENTLY OVER
ARIZONA...WILL DIP INTO NORTHERN MEXICO TONIGHT AND APPROACH FROM
THE WEST TOMORROW. A FEW SHOWERS WILL BE POSSIBLE IN THE MORNING
BUT GREATEST CHANCE FOR THUNDERSTORMS WILL BE IN THE AFTERNOON AND
EVENING HOURS ACROSS SOUTHEAST TEXAS. MAIN SEVERE THREAT WILL
CONTINUE TO BE STRONG WINDS AND ISOLATED TORNADOES...PRIMARILY
WITH ANY ISOLATED DISCRETE CELLS WHICH CAN DEVELOP OUT AHEAD OF
THE MAIN AREA OF THUNDERSTORMS WHICH WILL SET UP TO OUR WEST.
EXPECT THIS ACTIVITY TO DEVELOP INTO A LINE BY LATE EVENING AND
PUSH THROUGH THE REGION AFTER SUNSET. BY MIDNIGHT THE ACTIVITY
SHOULD BE MOVING INTO AREAS EAST OF I-45 WITH RAPID DRYING BEHIND
THE LINE. THE ONLY REAL CHANGE FROM THE PREVIOUS FORECAST IS A
TREND TOWARD SLIGHTLY HIGHER RAINFALL TOTALS WHICH MAY PRODUCE
SOME NUISANCE FLOODING ACROSS THE REGION SATURDAY EVENING.

SUNDAY LOOKS TO BE QUITE WARM FOR NOVEMBER WITH HIGHS IN THE MID
70S TO LOW 80S AHEAD OF A COLD FRONT WHICH WILL SWEEP THROUGH THE
REGION EARLY MONDAY MORNING. NO RAIN IS EXPECTED WITH THIS FRONT
OR A SECONDARY FRONT WHICH WILL ARRIVE ON TUESDAY. EXPECT DRY
WEATHER AND SEASONABLE TEMPERATURES FOR THANKSGIVING AND
ASSOCIATED TRAVEL DAYS. 38

MARINE...
SCA CONDITIONS BEYOND 20 NM TONIGHT AND SATURDAY WITH
SLIGHTLY LIGHTER WINDS SCEC FOR THE NEARSHORE WATERS. A PERIOD ON
THE BAYS MAY DEVELOP SATURDAY WHEN SCECS MAY BE NEEDED IN ADVANCE
OF THE BIG STORM SYSTEM COMING THROUGH. STRONG TO SEVERE
THUNDERSTORMS POSSIBLE SAT AFTN/NIGHT WITH ISOLATED WATERSPOUTS
AND GUSTY WINDS THEN IT TRANSITIONS TO SQUALLY CONDITIONS AS THE
SYSTEM ROTATES THROUGH IN THE EVENING AND EARLY MORNING SUNDAY.
COLD FRONT FINALLY COMES THROUGH ENDING THE SOUTHWESTERLY FLOW
TURNING IT TO THE NORTH AND SEAS GRADUALLY SUBSIDE SUNDAY. 45

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      62  74  58  78  47 /  30  90  80   0   0
HOUSTON (IAH)              62  76  61  79  51 /  20  80  90   0   0
GALVESTON (GLS)            65  74  66  78  56 /  20  70  90   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH SATURDAY AFTERNOON
     FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
     MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
     TO FREEPORT OUT 20 NM.

     SMALL CRAFT ADVISORY UNTIL 4 AM CST SUNDAY FOR THE FOLLOWING
     ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
     20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO
     60 NM.

&&

$$

DISCUSSION...40
AVIATION/MARINE...39


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