Daily General Weather Discussion Thread #9

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0334 AM CDT THU APR 10 2014

VALID 131200Z - 181200Z

...DISCUSSION...
THE SWRN U.S. SHORTWAVE TROUGH IS FORECAST TO RAPIDLY MOVE EWD
ACROSS THE SRN PLAINS AND LOWER MS VALLEY ON D4/SUN...WITH NUMEROUS
THUNDERSTORMS EVOLVING THROUGH THE PERIOD. A SURFACE LOW SHOULD
EXIST SOMEWHERE BETWEEN WRN OK AND NWRN TX DURING THE DAY...SHIFTING
SEWD AS A COLD FRONT DEVELOPS RAPIDLY SWD. AHEAD OF THE LOW...SLY
WINDS WILL BRING MID TO UPPER 60S F BOUNDARY LAYER DEWPOINTS TO THE
LOW/FRONT. MEANWHILE...RAPID COOLING ALOFT WILL OCCUR WITH THE UPPER
TROUGH WITH WARMER AIR ACROSS SWRN TX SPREADING NEWD HELPING TO
ERODE CAPPING.

WIND PROFILES WILL BECOME INCREASINGLY FAVORABLE FOR SEVERE STORMS
INCLUDING SUPERCELLS AHEAD OF THE COLD FRONT WITH A BROAD AREA OF
SWLY 40-50 KT 850 MB FLOW AND SUBSTANTIAL SPEED SHEAR WITH HEIGHT.
TIMING ISSUES EXIST REGARDING LEADING IMPULSES PRIOR TO THE COLD
FRONT ARRIVING WHICH WILL AFFECT WHERE THE STRONGEST FORCING FOR
ASCENT WILL BE. MODELS SUGGEST A FEATURE MOVING ACROSS THE ARKLATEX
IN THE 18-21Z TIME FRAME...THEN THE MAIN COLD FRONT LATER IN THE
DAY. TORNADOES...HAIL AND WIND WILL ALL BE POSSIBLE BEGINNING EARLY
AFTERNOON...WITH MORE OF A WIND AND HEAVY RAIN THREAT OVERNIGHT IF
AN MCS FORMS.

FOR THE MON/D5 PERIOD...THE AFOREMENTIONED SHORTWAVE TROUGH WILL
RAPIDLY CONTINUE EWD ACROSS THE GULF COAST STATES WITH COLD FRONT TO
THE W FROM THE MIDDLE OH VALLEY SWWD TO THE SABINE RIVER. MUCH OF
THE AIR MASS IS EXPECTED TO BECOME OVERTURNED BY PREVIOUS DAYS
CONVECTION...THEREFORE...PREDICTABILITY IS TOO LOW FOR D5.

RAIN AND STORMS WILL PERSIST ALONG THE FRONT INTO THE TUE/D6 PERIOD
ALONG THE E COAST...BUT THE SEVERE THREAT SHOULD BE MINIMAL BY THIS
TIME.

Let's see if we can get that nudged south for day 5 (monday) lol

HOUSTON:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
223 PM CDT THU APR 10 2014

.DISCUSSION...
IT IS MOSTLY SUNNY AND BREEZY THIS AFTERNOON ACROSS MUCH OF SOUTHEAST
TEXAS WITH SOUTH WINDS GENERALLY RUNNING IN A 15 TO 20 MPH RANGE WITH
HIGHER GUSTS. OVERNIGHT...AREA WILL SEE THESE WINDS EVENTUALLY COME
DOWN TO 5 TO 10 MPH INLAND AND 10 TO 15 MPH ALONG THE COAST. MOISTURE
LEVELS WILL BE ON THE RISE...AND SKIES ARE EXPECTED TO BECOME PARTLY
TO MOSTLY CLOUDY. THE WEEK WILL CLOSE OUT WITH MORE CLOUDS AND ANOTHER
DAY WITH WARM TEMPERATURES...AND THE SOUTH WINDS WILL NOT BE AS STRONG
AS THEY ARE TODAY. WE'LL REPEAT FRIDAY'S WEATHER ON SATURDAY...THEN
CONTINUE TO CALL FOR INCREASE RAIN CHANCES BEGINNING ON SUNDAY. RAIN
WILL REMAIN IN THE FORECAST INTO MONDAY AS THE NEXT DISTURBANCE AND
ASSOCIATED STRONG COLD FRONT WORK THEIR WAY EASTWARD ACROSS THE SOUTHERN
PLAINS STATES. SOME STRONG TO POSSIBLY SEVERE STORMS COULD DEVELOP SUNDAY
AFTERNOON AND EVENING UP NORTH (ROUGHLY ALONG AND NORTH OF A LINE FROM
COLLEGE STATION TO HUNTSVILLE TO LIVINGSTON)...BUT AT THIS TIME IT APPEARS
THAT THE BULK OF ANY SEVERE ACTIVITY THAT DOES DEVELOP IS ANTICIPATED
TO BE OFF TO OUR NORTH AND NORTHEAST. THE STRONG COLD FRONT WILL WORK
ITS WAY THROUGH SOUTHEAST TEXAS ON MONDAY MORNING AND THEN OFF THE COAST
AND THROUGH THE COASTAL WATERS MONDAY AFTERNOON WITH GUSTY NORTH TO
NORTHWEST WINDS DEVELOPING BEHIND THE BOUNDARY. SURFACE HIGH PRESSURE
BUILDING INTO THE AREA BEHIND THE FRONT WILL COOL THINGS DOWN FOR
TUESDAY...THEN A WARMUP WILL BEGIN DURING THE DAY ON WEDNESDAY AS THE
HIGH MOVES OFF TO THE EAST.

LAKE CHARLES:

THE NEXT MAIN WEATHER EVENT FOR THE AREA STILL LOOKS TO COME LATE IN
THE WEEKEND INTO EARLY NEXT WEEK AND GLOBAL MODELS ARE BEGINNING TO
COME INTO A LITTLE BETTER AGREEMENT REGARDING THE TIMING THE NEXT
FRONT. AN UPPER TROF WILL CROSS THE SWRN STATES SATURDAY NIGHT
INTO SUNDAY. THE LEAD IMPULSE ASSOCIATED WITH THIS SYSTEM WILL MOVE
OVER THE LOWER MS VALLEY SUNDAY NIGHT...HELPING TO USHER A COLD
FRONT TOWARD THE AREA. THE FRONT IS STILL PROGGED TO CROSS THE
AREA DURING THE DAY MONDAY...AND TIMING DIFFERENCES HAVE NARROWED
CONSIDERABLY FM A FEW DAYS AGO.

MOISTURE WILL DEEPEN AHEAD OF THE SYSTEM WITH PW WATER VALUES
REACHING 1.7 INCHES AND MEAN LAYER RH VALUES ABV 70 PERCENT. LIFT
ASSOCIATED WITH IMPULSES IN ADVANCE OF THE TROF WILL ALLOW FOR A
SLT TO LOW END CHC OF SHOWERS AND THUNDERSTORMS SUNDAY. RAIN
CHANCES WILL INCREASE SUNDAY NIGHT INTO MONDAY AS THE FRONT MOVES
INTO THE AREA...AND MAINTAINED INHERITED CHC POPS FOR THIS PERIOD.
SOME STRONG TO SVR STORMS COULD BE POSSIBLE SUNDAY NIGHT INTO
MONDAY MORNING AS WIND SHEAR PROFILES BECOME MORE FAVORABLE ALONG
WITH ENHANCED LIFT FM SFC CONVERGENCE ALONG THE FRONT. BEST
POTENTIAL LOOKS TO BE NORTH OF THE AREA BUT COULD AFFECT AT LEAST
THE NRN PERIPHERY OF THE CWA AS OUTLINED IN THE LATEST SPC DAY 4-8
OUTLOOK.

WOW I wasn't expecting this shift for day 3..



DAY 3 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0259 AM CDT FRI APR 11 2014

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTHERN PLAINS/OZARKS
TO THE MIDDLE/LOWER MS RIVER VALLEY...

CORRECTED FOR WORDING/DAY OF WEEK

...SYNOPSIS...
LONGWAVE TROUGH AMPLIFICATION WITH BROAD CYCLONIC UPPER FLOW IS
EXPECTED TO EVOLVE SUNDAY OVER THE CENTRAL CONUS...WITH MULTIPLE
SHORTWAVE IMPULSES OVERSPREADING THE REGION. A COLD FRONT WILL
ACCELERATE SOUTH-SOUTHEASTWARD ACROSS MUCH OF THE SOUTH-CENTRAL
PLAINS AND LOWER MO VALLEY/OZARKS THROUGH SUNDAY NIGHT.

...SOUTHERN PLAINS/OZARKS TO MIDDLE/LOWER MS RIVER VALLEY...
GIVEN THE LARGE-SCALE EVOLUTION AS PREVIOUSLY DESCRIBED...IT SEEMS
LIKELY THAT A LEAD/SOUTHERN STREAM IMPULSE AND ASSOCIATED SPEED MAX
WILL SPREAD EAST-NORTHEASTWARD FROM THE SOUTHERN PLAINS TO THE
MIDDLE MS RIVER VALLEY SUNDAY/SUNDAY NIGHT. AHEAD OF THE COLD
FRONT/SURFACE LOW...PERSISTENTLY STRONG SOUTHWESTERLY LOW-LEVEL
WINDS WILL CONTINUE TO TRANSPORT MOISTURE NORTH-NORTHEASTWARD WITHIN
AN INCREASINGLY BROAD WARM/MOIST SECTOR FROM EAST-CENTRAL PARTS OF
OK/TX TO THE OZARKS/LOWER-MIDDLE MS RIVER VALLEY.

AS THE AIR MASS DESTABILIZES THROUGH AFTERNOON...AMPLE FORCING FOR
ASCENT TIED TO THE AFOREMENTIONED SHORTWAVE TROUGH AND COLD FRONT
SHOULD INFLUENCE INCREASING TSTM DEVELOPMENT PARTICULARLY SUNDAY
AFTERNOON/EVENING. GREATER CERTAINTY FOR STRONGER DEEP CONVECTIVE
DEVELOPMENT WILL BE NEAR THE ADVANCING COLD FRONT ACROSS PARTS OF
OK/SOUTHEAST KS AND ADJACENT MO/KS. HOWEVER...OTHER MORE DISCRETE
STRONG/SEVERE STORMS INCLUDING SUPERCELLS WILL BE POSSIBLE ACROSS
ADDITIONAL PARTS OF EAST-CENTRAL TX/ARKLATEX WITHIN THE PRE-FRONTAL
WARM SECTOR AND NEAR THE DRYLINE EXTENDING SOUTHWARD ACROSS
SOUTH-CENTRAL OK INTO NORTH-CENTRAL/CENTRAL TX.

FAVORABLE WIND PROFILES WILL SUPPORT INITIAL SUPERCELLS...ALTHOUGH
INCREASINGLY UNIDIRECTIONAL WINDS /VEER-BACK-VEERING WINDS WITH
HEIGHT/ AND THE INFLUENCE OF THE COLD FRONT SUGGEST THAT
MULTICELLS/LINE SEGMENTS SHOULD EVOLVE DURING THE EVENING IN MOST
AREAS...WITH NEAR-COLD FRONTAL STORMS STEADILY BEING UNDERCUT BY THE
COLD FRONT /FROM NORTHWEST TO SOUTHEAST/. LARGE HAIL IS EXPECTED TO
THE PRIMARY HAZARD OVERALL...ALTHOUGH DAMAGING WINDS AND SOME
TORNADOES MAY BE POSSIBLE AS WELL.

Latest models have slowed the rain down. NAM doesn't have it coming through until Monday afternoon.