898
FXUS64 KSHV 270413
AFDSHV
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1013 PM CST FRI FEB 26 2021
AVIATION
FOR THE ARKLATEX TERMINALS, A STATIONARY FRONT LIES ALONG I-20
FROM KTYR TO KSHV TO KELD. CURRENT OBS IFR FOR KTXK/KELD AND ALL
GUIDANCE INDICATING LIFR WILL DVLP ON REST OF COLD SIDE SOON AND
WARM SIDE BEFORE DAYBREAK. L/V WINDS TO N WILL KEEP OVERNIGHT WITH
KLFK TO KMLU, S OF THE FRONT WILL PREVAIL S5-10KT OVERNIGHT
CLIMBING OVER THE BOUNDARY MAKING SHOWERS UNTIL IT LIFTS OUT TO N
AS A WARM FRONT ON SAT WITH SOME DZ AND -RA 12-15Z ENDING ALONG
WITH FOG. A FEW ISOLD TS MAY OCCUR IN THE AFTN AS GRADIENT AHEAD
OF NEXT IMPULSE BRINGS SHRA BACK IN FROM NW EARLY ON SUN. /24/
PREV DISCUSSION
/ISSUED 959 PM CST FRI FEB 26 2021/
UPDATE...
TO ADD PATCHY FOG TO THE OVERNIGHT FORECAST AND INTO MID MORNING.
SHORT TERM...
CLOUDY AND COOL IN THE NORTH WITH MOSTLY LOWER 50S AND A TIGHT
T/TD SPREAD, GIVING WAY TO LIGHT FOG IN MANY LOCALES AT 10PM.
HALF MILE NOW IN IDABEL IS THE WORSE SO FAR WITH QUARTER MILE IN
THE PAST. THE COOL AIR WILL HANG IN PLACE AND WITH TEMPS EASING
DOWN TOWARD DAYBREAK, THUS IT IS A GIVEN THAT THE FOG WILL GROW
THICKER. PERHAPS EVEN REQUIRING AN ADVISORY IN THE PREDAWN TO
DAYBREAK HOURS.
SO EXPECT SOME FOG, BUT ANY RAINFALL WHICH IS A GOOD CHANCE OVER
TOP OF THIS FRONTAL BOUNDARY, THAT WOULD HELP MIX THE AIR A BIT
AND COULD HOLD VISIBILITES ABOVE CRITERIA, SO WE WILL DEFER FOR
ANOTHER FEW HOURS AT LEAST IF POSSIBLE. THE HRRR DOES SHOW
ENHANCEMENT IN THE COVERAGE OF LIGHT SHOWERS DURING THE NEXT 6-12
HOURS AS THIS BOUNDARY LIFTS TO OUR N DURING MIDDAY ON SATURDAY.
THIS COULD PUSH THE MERCURY TOWARD 65 OR SO FOR EVEN DEQUEEN WHICH
WILL SCOUR LAST IN THE VALLEY. HIGHS NEAR 80 IN OUR SOUTHERN TIER
ARE REASONABLE CONSIDERING WE ARE STILL NEAR 70 DOWN THERE NOW
WITH THE BEST SHOT AT SOME FREE VITAMIN D VIA THE SUN. /24/
PREV DISCUSSION... /ISSUED 335 PM CST FRI FEB 26 2021/
SHORT TERM.../TONIGHT THROUGH SATURDAY NIGHT/
ACROSS THE CONUS, A SHORTWAVE TROUGH OVER THE NORTHERN ROCKIES
CONTINUES TO DIVE ESE TOWARDS THE CENTRAL PLAINS. AHEAD OF THE
TROUGH, MOST OF THE COUNTRY REMAINS IN SOUTHWEST FLOW ALOFT,
INCLUDING OUR REGION. LAST NIGHT'S SHORTWAVE THAT PRODUCED HEAVY
RAIN AND SEVERE HAIL ACROSS THE NORTHERN HALF OF THE REGION,
CONTINUES TO PUSH EASTWARD INTO THE SE CONUS, WITH SOME LINGERING
SHOWER ACTIVITY BETWEEN THE I-20 AND I-30 CORRIDOR IN WAKE OF THE
SYSTEM NEAR A THETA-E RIDGE. AT THE SAME TIME, THE FRONTAL BOUNDARY
THAT MOVED THROUGH THE REGION A COUPLE DAYS AGO CONTINUES TO SLOWLY
LIFT NORTHWARD AS A WARM FRONT. ITS CURRENTLY LOCATED ALONG A LINE
FROM NEAR RUSK TEXAS TO MANSFIELD LOUISIANA TO NEAR MONROE
LOUISIANA. IN WAKE OF THIS BOUNDARY, CLOUDS HAVE THINNED OUT AND
WARM AIR ADVECTION HAS ALLOWED TEMPS TO CLIMB INTO THE MID TO UPPER
70S. NORTH OF THE BOUNDARY, A BROAD STRATUS DECK REMAINS ACROSS THE
REGION, WITH SOME FOG JUST NORTH OF THE ADVANCING BOUNDARY. TEMPS
IN THIS REGION HAVE REMAINED STEADY IN THE LOW TO MID 50S.
NOT EXPECTING MUCH CHANGE FOR THE REMAINDER OF THE AFTERNOON AS
SHORT-TERM PROGS ONLY ADVANCE THE WARM FRONT A LITTLE TO THE NORTH
THROUGH THE OVERNIGHT PERIOD. HOWEVER, SHOWERS LOOK TO CONTINUE NEAR
THE THETA-E BOUNDARY ALONG WITH SOME POSSIBLE ISOLATED
SHOWER/THUNDERSTORM DEVELOPMENT ALONG THE WARM FRONT. EXPECT
OVERNIGHT LOWS IN THE UPPER 50S TO LOWER 60S SOUTH OF THE FRONT,
WITH MID 40S TO LOW 50S ACROSS THE REMAINDER OF THE REGION.
BY SATURDAY, THE SHORTWAVE IN THE NORTHERN ROCKIES WILL KICK OUT
INTO THE CENTRAL PLAINS WITH ANOTHER STRENGTHENING UPPER TROUGH ON
ITS HEELS DIVING SOUTHWARD INTO THE GREAT BASIN REGION. IN
RESPONSE, SOUTHERLY WINDS ACROSS THE SOUTH-CENTRAL CONUS WILL
INCREASE, AND THE WARM FRONT WILL START TO ADVANCE NORTHWARD
DURING THE DAY. IMPULSES WILL MOVE ACROSS THE REGION ALONG THE
FLOW, PROVIDING ENOUGH LIFT FOR PRECIP TO DEVELOP. THE BEST CHANCE
FOR CONVECTION WILL LIKELY BE NORTH OF THE I-20 CORRIDOR NEAR THE
ADVANCING FRONTAL BOUNDARY. EXPECT MUCH WARMER TEMPERATURES, AS
HIGHS IN WAKE OF THE FRONT WILL CLIMB INTO THE 70S TO NEAR 80
DEGREES IN SOME LOCATIONS. /20/
LONG TERM.../SUNDAY THROUGH FRIDAY/
LONGWAVE TROUGHING WILL DIVE SE THROUGH THE GREAT BASIN AND INTO THE
DESERT SW SUNDAY, BEFORE EVENTUALLY CLOSING OFF SUNDAY NIGHT OVER
SRN NM. THIS TROUGHING PATTERN WILL MAINTAIN DEEP SW FLOW OVER THE
REGION LATE THIS WEEKEND THROUGH AT LEAST THE FIRST HALF OF THE NEW
WORK WEEK, AND THUS THE ELEVATED SUBTROPICAL MOISTURE FEED WILL
CONTINUE FROM CNTRL TX THROUGH THE LOWER/MID MS VALLEY INTO THE OH
VALLEY. AT THE SFC, A SHALLOW COLD FRONT REMAINS PROGGED TO DRIFT SE
INTO THE REGION BY MIDDAY SUNDAY/SUNDAY AFTERNOON, WITH PVA EMBEDDED
IN THE DIRTY SW FLOW CONTRIBUTING TO AN INCREASE IN CONVECTION
DEVELOPMENT ALONG/AHEAD OF THE FRONT ALONG A SW TO NE ORIENTED THETA-
E AXIS AHEAD OF THE FRONT. HAVE MAINTAINED CONSISTENCY WITH T HE
PREVIOUS FORECAST WITH POPS INCREASING TO CATEGORICAL SUNDAY
AFTERNOON ACROSS MUCH OF NE TX/SW AR/NW LA, BUT DID TAPER POPS BACK
A BIT ACROSS THE SRN ZONES WHICH WILL BE FARTHER REMOVED FROM THE
AXIS OF GREATER LARGE SCALE ASCENT AND NEAR AND JUST AHEAD OF THE
FRONT. WITH THE DEEP LYR FLOW FAIRLY UNIDIRECTIONAL ALONG THE
FRONTAL SFC, CONVERGENCE ISN'T PROGGED TO BE PARTICULARLY DEEP, EVEN
AS SBCAPES RISE TO NEAR 1000 J/KG ACROSS THE WARM SECTOR AHEAD OF
THE FRONT. LAPSE RATES ALOFT ARE NOT IMPRESSIVE EITHER, BUT RATHER
AM EXPECTING CONVECTION TO REMAIN ALONG AND BEHIND THE FRONT, WITH
THE POTENTIAL FOR ADDITIONAL HEAVY RAINS TO FALL ACROSS THE ALREADY
SATURATED AREAS OF NE TX/SW AR SUNDAY AFTERNOON/EVENING, BEFORE
EVENTUALLY SPREADING SE INTO THE LOWER E TX/N LA/SCNTRL AR FROM THE
LATE AFTERNOON THROUGH THE OVERNIGHT HOURS. ATTM, MINOR FLOODING OF
LOW LYING, POOR DRAINAGE AREAS IS POSSIBLE ACROSS NE TX/SW AR WHERE
WIDESPREAD RAINFALL AMOUNTS OF 1.5-3.00+ INCHES FELL SINCE THURSDAY
AFTERNOON/EVENING, ALTHOUGH AREAS TO THE S SHOULD BE ABLE TO TAKE
THE RAINFALL. VERY WARM/HUMID CONDITIONS ARE EXPECTED SUNDAY
AFTERNOON AHEAD OF THE FRONT OVER LOWER E TX/N LA, WHERE MAX TEMPS
WERE BUMPED UP A COUPLE DEGREES OVER THE COOLER NBM, WITH THE FRONT
EXPECTED TO SHIFT S THROUGH THE REGION SUNDAY NIGHT, EXITING THE
AREA BEFORE DAYBREAK MONDAY.
THE POST-FRONTAL RAINS WILL CONTINUE OVER MUCH OF THE AREA MONDAY AS
ELEVATED ISENTROPIC ASCENT IN THE SW FLOW PERSISTS. HOWEVER, THE
AFOREMENTIONED CLOSED LOW OVER THE DESERT SW REMAINS PROGGED TO
SLOWLY SHIFT E INTO THE SRN PLAINS THROUGH MONDAY NIGHT, ALTHOUGH
CONSIDERABLE TIMING DISCREPANCIES STILL EXIST WITH THE SLOW
ECMWF/CANADIAN SLOWER THAN THE MORE PROGRESSIVE GFS ENTERING THE RED
RIVER VALLEY MONDAY AFTERNOON, WITH THE LATTER TWO PROGS ABOUT 9-12
HRS SLOWER. PREFER THE SLOWER MORE CONSISTENT SOLUTIONS, WITH LIKELY
POPS MAINTAINED OVER MUCH OF THE AREA MONDAY NIGHT, BEFORE DRY
SLOTTING UNDERCUTTING THE OPENING TROUGH TAPERING THE SHRA OFF FROM
W TO E TUESDAY, WHILE DRIER LOW LEVEL AIR ADVECTS S AHEAD OF SFC
RIDGING FROM THE OZARKS INTO THE MID MS VALLEY. TEMPS SHOULD RETURN
BACK TO NEAR SEASONAL NORMS BY WEDNESDAY WITH INCREASED INSOLATION,
WITH THE OUTLIER GFS STILL SUGGESTING ANOTHER DEVELOPING CLOSED LOW
ENTERING THE TX/OK PANHANDLES THURSDAY, NEARLY 24 HRS EARLIER THAN
THE ECMWF/CANADIAN. THE NBM CONTINUES TO TREND CLOSER TO THE GFS,
WITH SLIGHT CHANCE POPS OVER MUCH OF THE AREA WEDNESDAY NIGHT
THROUGH FRIDAY, BUT DID DELAY THE REINTRODUCTION OF POPS A BIT UNTIL
WEDNESDAY NIGHT, BUT CONFIDENCE REMAINS LOW WITH THIS SOLUTION AS WE
ROUND OUT THE WORK WEEK. /15/
PRELIMINARY POINT TEMPS/POPS
SHV 55 75 65 75 / 30 40 20 80
MLU 60 76 67 77 / 40 50 20 50
DEQ 46 65 57 68 / 20 80 70 80
TXK 51 68 62 70 / 30 60 50 80
ELD 51 70 61 74 / 50 50 40 80
TYR 54 73 64 73 / 20 60 20 80
GGG 54 73 64 75 / 30 50 20 80
LFK 62 78 65 77 / 20 30 10 50
SHV WATCHES/WARNINGS/ADVISORIES
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
24/20/15
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