Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 280244
AFDLCH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
844 PM CST TUE JAN 27 2015

.UPDATE...
THE LATEST UPPER AIR SOUNDING (28/00Z) FROM KLCH VERIFIES WHAT IS
SEEN ON WATER VAPOR IMAGERY...AS A DRY AIR MASS PREVAILS. SOME
LIGHT SOUTHERLY WINDS HAVE RISEN THE DEW POINTS SOME THIS EVENING
AT A FEW SPOTS. HOWEVER...WITH WINDS EXPECTED TO BE NEARLY
CALM...AND CLEAR SKIES WITH A DRY AIR MASS...OVERNIGHT LOW
TEMPERATURES STILL ON TRACK. WITH THIS...A FEW SITES MAY SEE SOME
SHALLOW GROUND FOG AS AIR TEMPERATURES LATER ON REACH DEW POINTS.
HOWEVER...THINKING IS THAT OVERALL AIR MASS IS TOO DRY TO SUPPORT
ANY SIGNIFICANT FOG DEVELOPMENT AND WILL NOT PLACE IN WEATHER
GRIDS AT THIS TIME. THEREFORE...NO CHANGES TO THE FORECAST FOR THE
EVENING UPDATE.

RUA

&&

.PREV DISCUSSION... /ISSUED 519 PM CST TUE JAN 27 2015/

DISCUSSION...
28/00Z TAF ISSUANCE.

AVIATION...
HIGH PRES RIDGING SW ACRS THE AREA WILL MOVE SLOWLY EAST THROUGH
WEDNESDAY. THE RESULT WILL BE VFR CONDITIONS WITH MAINLY SKC SKIES
AND LT VRBL WINDS WHICH WILL VEER MORE SELY DURING THE DAY
TOMORROW. 24

PREV DISCUSSION... /ISSUED 342 PM CST TUE JAN 27 2015/

DISCUSSION...
LATEST WATER VAPOR IMAGERY SHOWS SUBSIDENCE AND A RATHER DRY AIR
MASS ACROSS THE REGION. MEANWHILE...A WEAK SURFACE RIDGE ALSO LIES
ACROSS THE REGION. THE COMBINATION OF THE TWO IS HELPING TO PROVIDE
SUNNY SKIES...LIGHT WINDS...WHICH IN TURN IS ALLOWING FOR RATHER
WARM AIR TEMPERATURES FOR LATE JANUARY...FOR LOCATIONS AWAY FROM
THE GULF OF MEXICO...WITH READINGS IN THE MID TO UPPER 70S...SOME
15F DEGREES ABOVE NORMAL.

SURFACE RIDGE WILL SLIDE OFF TO THE EAST ON WEDNESDAY...WITH
SOUTHERLY WINDS OFF THE GULF GRADUALLY RETURNING TO THE FORECAST
AREA. THIS WILL HELP MODIFY THE AIR MASS AT THE SURFACE WITH THE
MORE MOIST AND COOLER GULF AIR HELPING TO KEEP TEMPERATURES ON
WEDNESDAY LOWER THAN WHAT IS OCCURRING TODAY. HOWEVER...THESE
VALUES WILL STILL BE SOME 10F DEGREES ABOVE NORMAL. THE INCREASE
IN GULF LOW LEVEL MOISTURE WILL ALSO BRING ABOUT THE CHANCE FOR
AT-LEAST PATCHY FOG DEVELOPMENT ON WEDNESDAY NIGHT INTO THURSDAY
MORNING.

A SHORT WAVE IS EXPECTED TO COME DOWN THE SIDE OF THE WESTERN U.S.
RIDGE LATE TOMORROW AND MOVE EASTWARD ACROSS THE PLAINS AND GREAT
LAKES THROUGH THURSDAY. THIS SYSTEM WILL HELP PUSH A WEAK COLD
FRONT ACROSS THE FORECAST AREA ON THURSDAY EVENING. MOISTURE
PROFILES DO HAVE PRECIPITABLE WATER VALUES NEARING 1 INCH WITH
MEAN RH BRIEFLY OVER 50 PERCENT AHEAD OF THE FRONT. HOWEVER...TIME
HEIGHTS SHOW THIS MOISTURE TO BE RATHER SHALLOW AND MAINLY BELOW
5K FEET. WITH UPPER LEVEL DYNAMICS ALSO STAYING WELL TO THE NORTH
WITH THIS FRONT...DO NOT EXPECT ANY SIGNIFICANT SHOWER ACTIVITY TO
DEVELOP WITH IT...AND WILL KEEP FRONTAL PASSAGE AS DRY.

COOLER CONDITIONS ARE EXPECTED BEHIND THE FRONT FOR FRIDAY WITH
HIGH TEMPERATURES BACK CLOSER TO SEASONAL NORMS.

CUT OFF UPPER LEVEL LOW IS STILL EXPECTED TO FORM OVER THE
SOUTHWEST U.S. BY THE END OF THE WEEK AND MOVE DOWN TOWARD THE
BAJA CALIFORNIA/NORTHWEST OLD MEXICO AREA OVER THE WEEKEND.
STRENGTHENING SOUTHERN JET WILL INCREASE PACIFIC MOISTURE ACROSS
THE FORECAST AREA...AS WELL AS PUSH DISTURBANCES EJECTING OUT OF
THE UPPER LEVEL LOW TOWARD THE FORECAST AREA. THIS WILL BRING
ABOUT A CHANCE OF SHOWERS BY SATURDAY.

SURFACE HIGH PRESSURE THAT BUILDS IN BEHIND THE COLD FRONT ON
THURSDAY NIGHT WILL PUSH OFF TO THE EAST BY SATURDAY NIGHT...AND
THIS WILL ALLOW SOUTHERLY WINDS TO DEVELOP DURING THIS TIME. THIS
WILL ALSO HELP INCREASE MOISTURE PROFILES AS LOW LEVEL GULF
MOISTURE WILL BE ADDED TO THE EAST PAC MOISTURE. PRECIPITABLE
WATER VALUES INCREASE FOR SATURDAY NIGHT INTO SUNDAY TO BETWEEN
1.3 AND 1.5 INCHES...WITH MEAN RH OVER 90 PERCENT...BOTH
RESPECTABLE NUMBERS FOR THE COOL SEASON. INCREASING LIFT FROM
DISTURBANCES IN THE SOUTHERN JET...AS WELL AS AN APPROACHING COLD
FRONT...THAT WILL MOVE ACROSS LATE SUNDAY...WILL TAP INTO THE
DECENT MOISTURE TO PROVIDE A LIKELIHOOD OF SHOWERS FOR THE
SATURDAY NIGHT INTO SUNDAY PERIOD. AT THIS POINT...SURFACE
INSTABILITY REMAINS RATHER MEAGER...SO WILL KEEP ACTIVITY AS JUST
SHOWERS...AND NOT MENTION THUNDER.

SHOWERS WILL GRADUALLY END FROM THE NORTHWEST TO THE SOUTHEAST ON
SUNDAY NIGHT AS DRIER AIR MOVES IN BEHIND THE FRONT.

RUA

MARINE...
LIGHT SOUTHERLY WINDS ARE EXPECTED ON WEDNESDAY AS A SURFACE HIGH
PRESSURE SYSTEM MOVES OFF TO THE EAST. THESE SOUTHERLY WINDS WILL
BRING BACK A MORE MOIST MARINE AIR MASS INTO THE REGION...AND WITH
DEW POINTS NEARING THE NEAR SHORE WATER TEMPERATURES...AT-LEAST
SOME PATCHY SEA FOG IS EXPECTED TO DEVELOP ON WEDNESDAY NIGHT INTO
THURSDAY. A COLD FRONT WILL MOVE ACROSS THE COASTAL WATERS ON
THURSDAY EVENING...ENDING FOG CHANCES AND BRINGING MODERATE NORTHERLY
WINDS.

WIND SPEEDS WILL REMAIN MODERATE AND BECOME EASTERLY ON SATURDAY
THEN SOUTHEASTERLY SATURDAY NIGHT INTO SUNDAY AS AN UPPER LEVEL
DISTURBANCE HELPS FORM AN AREA OF LOW PRESSURE OVER TEXAS...THAT
WILL MOVE ACROSS NORTHERN LOUISIANA. THIS SYSTEM WILL ALSO BRING
WIDESPREAD SHOWER ACTIVITY UNTIL ANOTHER COLD FRONT MOVES ACROSS
LATE SUNDAY.

RUA

&&

.PRELIMINARY POINT TEMPS/POPS...
KLCH  46  69  52  73  49 /   0   0   0  10  10
KBPT  47  72  53  73  50 /   0   0   0  10  10
KAEX  41  71  49  73  43 /   0   0   0   0  10
KLFT  45  69  52  74  48 /   0   0   0   0  10

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&

$$







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