April 13th - 14th Severe Weather/Heavy Rain Threat

This morning's AFD:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
426 AM CDT SAT APR 12 2014

.LONG TERM...

SUNDAY NIGHT THROUGH THE END OF THE FORECAST.

SHORTWAVE MOVING OUT OF TEXAS INTO THE MIDDLE AND LOWER
MISSISSIPPI RIVER VALLEY WILL HAVE PLENTY OF MOISTURE TO WORK
WITH AS PRECIPITABLE WATER VALUES RAMP UP TO BETWEEN 1.75 AND 2
INCHES BY SUNDAY NIGHT AND MONDAY MORNING.

TIMING AND AMPLITUDE DIFFERENCES CONTINUE TO EXIST WITH THE
LONGWAVE TROF EXPECTED TO MOVE ACROSS THE AREA ON MONDAY. THE
OPERATIONAL EURO SOLUTIONS CONTINUE TO BE SLOWEST/DEEPEST WITH THE
TROF...BUT ONLY ABOUT 6 HOURS SLOWER THAN GFS/NAM THROUGH TUESDAY.
SOUTHERN STREAM SHORTWAVE MOVES ACROSS THE AREA LATE SUNDAY NIGHT
WITH ACTUAL COLD FRONT ONLY JUST ENTERING NORTHWEST LOUISIANA BY
EARLY MONDAY MORNING. THUNDERSTORMS IN ADVANCE OF THE FRONT COULD
AFFECT WESTERN PORTIONS OF THE AREA BY SUNRISE ON MONDAY AS THE
SOUTHERN STREAM SHORTWAVE WEAKENS. A FEW OF THESE STORMS COULD BE
STRONG TO SEVERE NEAR THE ATCHAFALAYA RIVER LATE SUNDAY NIGHT. A
STRONGER NORTHERN STREAM SHORTWAVE WILL PUSH THE COLD FRONT
THROUGH THE AREA MONDAY AFTERNOON AND MONDAY NIGHT. LOW LEVEL WIND
FIELDS WILL BE MORE CONDUCIVE FOR SEVERE THUNDERSTORM DEVELOPMENT
WITH THE FIRST SHORTWAVE...WHILE THE INSTABILITY AND UPPER WINDS
WILL BE MORE CONDUCIVE WITH THE SECOND SHORTWAVE. SPC HAS
OUTLOOKED THE ENTIRE AREA FOR A SLIGHT RISK MONDAY AFTERNOON AND
EVENING WITH THE SECOND SHORTWAVE. MOST LIKELY MODE WOULD BE
SQUALL LINE WITH EMBEDDED SUPERCELLS. MAIN THREAT WOULD BE
DAMAGING WIND...WHILE HAIL AND AN ISOLATED TORNADO OR TWO CANNOT
BE RULED OUT. HEAVY RAIN COULD ALSO BECOME A PROBLEM WITH TWO
ROUNDS OF CONVECTION EXPECTED. BETWEEN SUNDAY NIGHT AND TUESDAY
MORNING...MUCH OF THE AREA COULD SEE TWO TO THREE INCHES OF
RAIN...WHICH WOULD LIKELY BRING SIGNIFICANT RISES TO AREA RIVERS
AGAIN.

Severe parameters have been slowly ticking upward with the past few runs of the models. GFS and Euro showing ample CAPE across Louisiana and Mississippi for Monday afternoon. Wind profiles seem seem sufficient for rotating storms. Damaging winds is the biggest threat in my opinion. 

Here's the hodograph for SELA by the GFS for Monday midday...again the hook shape which is indicative of rotating storms:

It would really be nice to have her for Sunday and Monday:


ALERT ADMINISTRATIVE MESSAGE
NATIONAL WEATHER SERVICE LAKE CHARLES LA
900 AM CDT SAT APR 12 2014

TO: SRH...HGX...SHV...JAN...LIX

FROM: WFO LCH

SUBJECT: KPOE WSR-88D

THE FORT POLK WSR-88D...KPOE...HAS SUFFERED A COMMUNICATIONS
FAILURE. MAINTENANCE PERSONNEL HAVE BEEN CONTACTED BUT NO
ESTIMATE OF RESTORATION TIME IS AVAILABLE. THE RADAR WILL BE
OUT OF SERVICE UNTIL FURTHER NOTICE.

There does appear to be some convective inhibition on Monday which may put a damper on some of the weather early on.

Monday 12z:


Monday 18z (less convective inhibition):

Another long discussion from JACKSON:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
259 PM CDT SAT APR 12 2014

...EXPECT SOME SEVERE STORMS ALONG WITH HEAVY RAINFALL LATE SUNDAY
NIGHT INTO MONDAY EVENING...

.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)...
THE FORECAST WILL CONTINUE TO BE CENTERED ON THE PERIOD FROM
MIDNIGHT SUNDAY NIGHT INTO MONDAY EVENING FOR SOME SEVERE STORMS
ALONG WITH HEAVY RAINFALL AND FLOODING. THE LASTEST 12Z FORECAST
MODELS CONTINUE TO SHOW DECENT AGREEMENT ON THE OVERALL PATTERN OF
SYSTEM DEVELOPMENT. THE CONCERN IS STILL FOCUSED ON WHAT AREAS OF
THE REGION WILL HAVE THE WORST WEATHER. IT WILL DEPEND ON HOW THINGS
SET UP AFTER THE FIRST WAVE MOVES THROUGH THE REGION AS FAR AS ANY
LINGERING BOUNDARY IS CONCERN. THERE IS ENOUGH CERTAINTY THAT WE ARE
LOOKING AT TWO DIFFERENT TIME FRAMES FROM EACH OF THE TWO SHORT
WAVES.

LATEST SATELLITE IMAGERY SHOWS THE STORM SYSTEM PUSHING OVER THE
WESTERN CONUS AS NORTHERN STREAM ENERGY HAS MERGED WITH IT. THE SUBTROPICAL
JET WAS PUSHING PACIFIC MOISTURE TOWARD THE REGION IN THE SOUTHERN
STREAM. UNDER PARTLY CLOUDY SKIES READINGS ACROSS THE REGION WERE IN
THE UPPER 70S TO THE LOWER 80S UNDER BREEZY SOUTHERLY WINDS.

FOR TONIGHT THROUGH PART OF SUNDAY EVENING...EXPECT A GENERALLY
QUIET PATTERN AS A STORM SYSTEM APPROACHES THE REGION FROM THE WEST.
MODEL SOUNDINGS AND CROSS SECTIONS SHOWS ANOTHER ROUND OF LOW
STRATUS COMING INTO THE REGION TOWARD DAWN...WHICH WILL LIFT BY MID
TO LATE MORNING. THERE MAY BE A LITTLE BIT OF PATCHY FOG IN THE
SOUTH BY EARLY SUNDAY. SO PUT IN SOME PATCHY FOG IN THE GRIDS.
OTHERWISE THE REGION WILL BE UNDER THE WARM SECTOR CAP WITH BREEZY
SOUTHERLY WINDS ON SUNDAY WITH GUSTS AROUND 25 MPH. THE WINDS SHOULD
STAY UNDER WIND ADVISORY CRITERIA ON SUNDAY. THE GFS AND EURO MODELS
TRIES TO BREAK OUT SOME SHOWERS IN THE WEST DURING THE DAY...BUT THE
NAM KEEPS IT DRY. BUT DONT THINK THAT WILL HAPPEN WITH THE CAP IN
PLACE...WHICH IS VERIFIED BY THE NATIONAL WRF MODELS.

THE MODELS CONTINUE TO INDICATE A TWO SHORT WAVE STORM SYSTEM WITH
THE FIRST SMALLER SHORT WAVE AFFECTING THE REGION LATE SUNDAY NIGHT
INTO MONDAY MORNING. THERE WILL BE ENOUGH ASCENT TO REMOVE THE CAP
LATE SUNDAY NIGHT. MODELS SHOWS THAT WE WILL GET SOME DECENT INFLOW
OVER A GOOD THETA E AXIS OF AROUND 330K. THE MUCAPE VALUES WILL RUN
AROUND 1000-1900 ACROSS THE WEST AS WELL AS 200-800 ACROSS THE EAST
AS SHOWALTERS WILL RUN AROUND -1 TO -4 IN THE WEST HALF. ALL MODELS
INCLUDING THE EURO INCREASE INSTABILITY BY 12Z MONDAY. 0-1 KM BULK
SHEAR WILL BE AROUND 40 KNOTS IN THE WEST AND WILL BE WEAKER IN THE
EAST HALF. THIS WILL BE DUE TO THE STRONG LOW LEVEL FLOW IN RESPONSE
TO THE APPROACHING FIRST SHORT WAVE. WITH THIS IN MIND LOOKING AT A
LARGE MCS WITH SOME BOWING LINE SEGMENTS TO AFFECT MAINLY THE WEST
HALF FROM LATE SUNDAY NIGHT UNTIL MONDAY MORNING. NATIONAL NMM WRF
MODELS SHOWS CONVECTION DEVELOPING BY 06Z WITH AN MCS ACROSS THE MS
RIVER AND SPREADING ACROSS MAINLY THE NORTH HALF DURING SUNDAY
NIGHT. THE ARW WRF SHOWS A LINE BOWING ACROSS THE REGION BETWEEN
06Z-12Z SUNDAY. THE PRIMARY RISK WILL BE LARGE HAIL...DAMAGING
WINDS AND SOME TORNADOES. BELIEVE THAT THE MCS WILL BE PROGRESSIVE
ENOUGH FOR ONLY LOCALLY HEAVY RAIN ISSUES WITH THE FIRST SHORTWAVE
THROUGH EARLY MONDAY MORNING. WILL CONTINUE TO INDICATE A LIMITED
TORNADO RISK FOR ALL OF THE CWA. BASED ON SIMILAR 12Z MODELS...WILL
CONTINUE TO SHOW AN ELEVATED SVR WX RISK FOR DAMAGING WINDS ALONG
AND WEST OF A GREENWOOD TO BRANDON TO LAUREL LINE. MAIN TIMING FOR
THIS WILL BE FROM MIDNIGHT TO ROUGHLY AROUND 8 AM MON MORNING. THE
TORNADO RISK WILL DIMINISH AROUND THIS TIME AS WELL AS LOW LEVEL
FLOW VEERS AND WEAKENS.

AS WE GO INTO LATE MONDAY MORNING INTO MONDAY EVENING...WE WILL LOSE
OUR 0-1 KM FORCING FOR ANY TORNADO POTENTIAL. WE WILL GET STRONG
ASCENT AS THE PRIMARY UPPER TROUGH APPROACHES THE REGION. MODELS
SHOWS THAT AS THE SECOND WAVE APPROACHES WE WILL GET SOME LIGHT
CORFIDI VECTORS IN THE MORNING...WHICH MAY BRING SOME BACKBUILDING
OF HEAVY CONVECTION. WITH PWATS AROUND 1.8 INCHES ALSO LOOKING AT
SOME HEAVY RAIN POTENTIAL MONDAY AFTERNOON INTO MONDAY EVENING. WE WILL HAVE
ENOUGH DEEP LAYER SHEAR AND GOOD SHALLOW CAPE OF AROUND 3000 J/KG
ALONG...INCREASING LAPSE RATES AND GOOD MOISTURE TRANSPORT. SO THERE
IS THE CONCERN FOR THE HEAVY RAIN WHICH WILL AGGRAVATE SATURATED
SOILS FOR SOME FLASH FLOODING AND AFFECT CURRENT RIVER FLOODING
ISSUES. OUR HYDROLOGIST WILL ISSUE A HYDROLOGIC OUTLOOK TO ADDRESS
THE RIVER ISSUES. THE LATEST 12Z GFS SHOWS AROUND 2 TO AROUND 3.5
INCHES ACROSS THE MID TO UPPER PEARL RIVER BASIN. THE 12Z EURO SHOWS
WIDESPREAD 2-3 INCHES ACROSS CENTRAL MISS. SO WITH THIS IN MIND HAVE
INCREASED RAINFALL AMOUNTS TO 2-4 INCHES WITH LOCALLY 4 PLUS INCHES
POSSIBLE THROUGH MONDAY EVENING. THE LOCATION OF THE WORST WEATHER
AREAS WILL BE TOUGH TO PIN DOWN AT THIS TIME. AS NOTED ABOVE IT WILL
DEPEND ON HOW THINGS SET UP AFTER THE FIRST SHORT WAVES PASSES
THROUGH. THIS HAS TO DO WITH THE LINGERING BOUNDARY SETUP FOR
CONVECTIVE DEVELOPMENT. AS FAR AS SEVERE POTENTIAL IS CONCERN MODEL
SOUNDINGS SHOWS THAT HODOGRAPH AND WIND PROFILES FAVOR BOWING LINE
SEGMENTS AND SUPERCELLS. SURFACE LIFTED INDEXES WILL BE AROUND -5 TO
-8. THE PRIMARY RISK WILL BE DAMAGING WINDS AND LARGE HAIL. WILL
CONTINUE TO INDICATE THE FLOODING AND SEVERE THREAT IN THE
HWO/GRAPHICS WITH THE TIMING FROM MAINLY NOON TO 9 PM. THE COLD
FRONT WILL BE EXITING THE REGION ON MONDAY EVENING BRINGING THE
CONVECTIVE EVENT TO AN END AS THE STORMS PUSH EAST OF THE REGION.
EXPECT ENOUGH SOME POST FRONTAL SHOWERS AND EMBEDDED THUNDERSTORMS
DURING THE NIGHT AS SOUTHWEST FLOW ALOFT CONTINUES TO BRING IN
MOISTURE AND SOME ELEVATED INSTABILITY. THE EMBEDDED CONVECTION WILL
EXIT THE REGION BY EARLY TUESDAY. EXPECT SOME COOL READINGS BEHIND
THE FRONT FOR TUESDAY MORNING WITH LOWS DIPPING INTO THE UPPER 30S
IN THE NORTHWEST DELTA REGION FROM GUSTY NORTHWEST WINDS BEHIND THE
STRONG COLD FRONT.