Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 300355 AAB
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
955 PM CST THU JAN 29 2015

.UPDATE...
SHOWERS REMOVED FROM THE FORECAST THIS EVENING...OTHERWISE NO MAJOR
CHANGES NEEDED.

&&

.DISCUSSION...
COLD FRONT IS JUST ABOUT THROUGH THE AREA THIS EVENING...WITH NW FLOW
PRETTY WELL ESTABLISHED IN THE WAKE OF THE SFC BOUNDARY. LOW CLOUDS
HAVE ALSO SPREAD EWD ACROSS MUCH OF THE AREA BEHIND THE DEPARTING
FRONT. THESE CLOUDS...ALONG WITH THE INCREASING WIND...HAVE KEPT TEMP
TRENDS FROM DROPPING QUICKLY...EVEN WITH THE PASSAGE OF A COLD FRONT.
HOWEVER...THE INFLUX OF DRIER AIR SHOULD ALLOW FOR TEMPS TO STEADILY
FALL MORE INTO THE 30S OVERNIGHT...AS SFC WINDS GRADUALLY DIMINISH.
SOME LIGHT RETURNS ON AREA RADARS N OF THE AREA MAY SKIRT THE FAR ERN
ZONES LATER THIS EVENING AS WELL IN THE FORM OF SOME VERY LIGHT RAIN
OR DRIZZLE...ALTHOUGH THE INFLUX OF DRIER AIR MAY KEEP ANY OF THIS
LINGERING MOISTURE FROM REACHING THE SFC. IN ANY CASE...THE PROB FOR
ISO SHOWERS LOOKS TO HAVE ENDED FOR AREAS ALONG/E OF I-65 WITH THE
PASSING FRONT...AND AS SUCH HAS BEEN REMOVED FROM THE FORECAST THIS
EVENING. WINDS/GUSTS HAVE ALSO BEEN REFRESHED BASED ON THE LATEST
TRENDS...BUT OVERALL NO MAJOR CHANGES ARE NEEDED WITH THE AFTERNOON
FORECAST PACKAGE AT THIS POINT.

09

&&

.AVIATION...
/ISSUED 540 PM CST THU JAN 29 2015/
FOR 00Z TAFS...A COLD FRONT WAS BEGINNING TO CROSS INTO NW AL THIS
EARLY THU EVENING. SFC WINDS BEHIND THE FRONT WERE TURNING TOWARD THE
NW AROUND 10-15KT WITH HIGHER GUSTS...AND THIS GENERAL TREND SHOULD
EVENTUALLY SPREAD INTO THE AREA LATER THIS EVENING WITH THE FRONTAL
PASSAGE. LOW CLOUDS...WITH BASES AT/JUST ABOVE 3K FT...WERE ALSO
TRAILING THE SFC BOUNDARY...AND THESE ALSO SHOULD MOVE EWD INTO THE
AREA HEADING INTO THE OVERNIGHT HRS. OVERALL CONDS/CLOUD COVER SHOULD
THEN BEGIN TO IMPROVE GOING INTO THE LATE MORNING HRS FRI...AS THE
INFLUX OF DRIER AIR INCREASES OUT OF THE NNW.

09

&&

.PREV DISCUSSION...
/ISSUED 328 PM CST THU JAN 29 2015/
UNDER MOSTLY CLOUDY SKIES...RATHER WARM FOR LATE JANUARY WEATHER
PREVAILED OVER THE TENNESSEE VALLEY. HOWEVER...THIS WILL ALL
CHANGE IN A SHORT ORDER...AS A COLD FRONT NOW REACHING FAR NW
ALABAMA SWEEPS ACROSS THE AREA LATE THIS AFTERNOON AND EVENING.
HIGHS THUS FAR HAVE WARMED INTO THE LOW/MID 60S...WITH SW WINDS OF
OF 10-20 MPH. SHOWER ACTIVITY THAT AFFECTED THE AREA HAS
DISSIPATED...MAINLY BECAUSE OF A RATHER DRY LOWER/MID ATMOSPHERE
AND MINIMAL FORCING.

A BUSY MID/UPPER LEVEL CONTINUED ACROSS THE GREAT NORTH AMERICAN
DOMAIN. A SURGE OF MOISTURE MOVING NORTHWARD FROM THE SUBTROPICAL
PACIFIC SOUTH OF THE BAJA WAS OVERSPREADING THE DESERT SW AND
SOUTHERN ROCKIES. SOME OF THOSE CLOUDS WERE MOVING EASTWARD...
GETTING INGESTED IN THE NORTHERN STREAM...WERE MOVING ACROSS THIS
REGION AS OF THIS WRITING. AN UPPER LEVEL LOW JUST WEST OF THE
MOISTURE PLUME WILL MOVE OVER NORTHERN MEXICO OVER THE NEXT COUPLE
DAYS...AND HELP GENERATE A NEW SYSTEM THAT WILL BRING WIDESPREAD
RAIN/SNOWS TO SOUTHERN CONTINENTAL DIVIDE REGION. AS THE SYSTEM
MOVES EASTWARD...IT WILL BRING RAIN CHANCES TO OUR AREAS TO START
A NEW WEEK.

FOR THE SHORT TERM...THE ABOVE MENTIONED COLD FRONT APPROACHING
FROM THE NW WILL USHER COLDER AIR ACROSS THE FORECAST AREA. GIVEN
LACK OF ON-GOING PRECIP AND EXPECTED DRY CONDITIONS (DESPITE LIFT
FROM THE FRONT)...ONLY HAVE A SLIGHT RAIN CHANCE IN FOR OUR
EASTERN AREAS EARLY THIS EVENING...WITH ALL PRECIP ENDING BY
MIDNIGHT. GIVEN HOW DRY IT IS AND A SHORT DURATION OF ANY
PRECIP...NO WINTRY WEATHER ISSUES ARE ANTICIPATED TONIGHT.

DRY BUT COOL WEATHER WILL PREVAIL THE LAST COUPLE OF DAYS OF
JANUARY...AS HIGH PRESSURE OVER THE CENTRAL PLAINS BUILDS TOWARD
THE MID ATLANTIC BY LATE SATURDAY. DESPITE THE SUN...HIGHS WILL
ONLY RISE INTO THE MID 40S TOMORROW...AND UPPER 40S/NEAR 50 ON
SAT. IN THE MEANWHILE...THE SYSTEM AFFECTING THE SOUTHERN ROCKIES
AND NEARBY PLAINS WILL MOVE THIS DIRECTION. A SURFACE LOW WITH
THIS SYSTEM SHOULD FORM OVER TEXAS DURING SUNDAY...AND HEAD ENE
TOWARD THE REGION. MODEL WISE...BOTH THE GFS/ECMWF TRACK THE LOW
ACROSS THE CUMBERLAND/OHIO RIVER VALLEYS (NORTH OF US)...PLACING
US IN THE WARMER/WETTER REGION OF THE SYSTEM. DESPITE THE
MOISTURE...INSTABILITY LEVELS REMAIN ON THE LOW SIDE...THEREFORE
NO THUNDER IS EXPECTED. A COLD FRONT WITH THIS SYSTEM SHOULD SWEEP
BY THE AREA SUN EVENING...BRINGING NOTABLY COLDER AIR ACROSS THE
VALLEY. BOTH THE GFS/EC AND THE CANADIAN HAVE IT COLD ENOUGH FOR
THE PRECIP TO BECOME MIXED WITH SNOW BEFORE DAYBREAK MON. GIVEN
DRIER AIR INVADING FROM THE NW...HAVE ENDED ANY SNOWS DURING MON
MORNING. NO WINTRY WEATHER WOES ARE EXPECTED. HIGH TEMPERATURES ON
MON WILL ONLY RISE INTO THE 30S WITH CHILLY NW WINDS OF 5-15 MPH.

THE GLOBAL MODELS ALL SHOW HIGH PRESSURE BUILDING OVER THE NW
TERRITORIES/EASTERN ALASKA...MAINLY IN THE 1040S TO 1050S MB
RANGE. COLD AIR SPILLING SE IN THE PREVAILING NW FLOW WILL KEEP
COOLER THAN NORMAL CONDITIONS GOING FOR MUCH OF NEXT WEEK. IN THIS
COLD REGIME...ANOTHER SOUTHERN STREAM SYSTEM WILL AFFECT THE AREA
DURING THE MIDDLE OF NEXT WEEK. TEMPERATURES SHOULD WARM UP ENOUGH
TO KEEP IT AN ALL RAIN AFFAIR...BUT HAVE IT ENDING AS A RAIN/SNOW
MIX WED NIGHT. NO WINTRY WEATHER ISSUES ARE EXPECTED.

RSB

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE
AT WEATHER.GOV/HUNTSVILLE.



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