FXUS64 KHUN 051439
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
839 AM CST SAT DEC 5 2009
.UPDATE...CANCELED WINTER WX ADVISORY
&&
.DISCUSSION...DID A QUICK UPDATE TO REMOVE WINTER WX ADVISORY FOR
OUR NERN ZONES...AS RADAR SHOWS SNOW HAS MOVED EAST OF OUR CWA. 5H
TROF AXIS IS ALONG THE GA/AL LINE ATTM AND WILL QUICKLY MOVE EAST
TODAY. BEHIND THE UPPER TROF WAS A LARGE AREA OF HIGH PRESSURE...THUS
EXPECT CLOUDS TO CONTINUE TO DECREASE TODAY. IT WILL BE COLD TODAY
DUE TO GOOD CAA...WITH AFTN HIGHS STRUGGLING TO REACH THE LOWER
40S.
AS FOR SNOW AMOUNTS...MOST REPORTS WERE BETWEEN ONE HALF OF AN
INCH TO ONE INCH...MAINLY EAST OF I65. WITH TEMPS ARND FREEZING
THIS MRNG...THERE HAVE BEEN SEVERAL REPORTS OF ACCIDENTS IN THE HUN AREA
WITH SLICK SPOTS ON ROADS..ESPECIALLY BRIDGES AND OVERPASSES.
TEMPS ARE EXPECTED TO GO ABOVE FREEZING BEGINNING ARND 10 AM.
&&
.PREV DISCUSSION... /ISSUED 535 AM CST SAT DEC 5 2009/
UPDATE...FOR 12Z AVIATION DISCUSSION
AVIATION....
ONE LAST SNOW BAND WILL IMPACT KHSV THROUGH ABOUT 1230Z...AND AFTER
CLOUD DECK SCATTERS /BY ABOUT 13Z/ VFR CONDITIONS ARE EXPECTED
THROUGH THE PERIOD AS HIGH PRESSURE BUILDS INTO THE AREA FROM THE
WEST. VFR CONDITIONS ARE EXPECTED AT MSL THROUGH THE PERIOD.
DISCUSSION.../ISSUED AT 327 AM CST SAT DEC 5 2009/
LIGHT SNOW CONTINUING TO FALL ACROSS PORTIONS OF THE CENTRAL
TENNESSEE VALLEY EARLY THIS MORNING AHEAD OF FAST-MOVING UPR LVL
TROUGH. SEVERAL REPORTS...IN CONJUNCTION WITH AREA WEB CAMS...HAVE
INDICATED A DUSTING UP TO 1/2 INCH OF SNOW BLANKETING MUCH OF
NORTH-CENTRAL AND NORTHEAST ALABAMA...INCLUDING 0.3" HERE AT THE NWS
OFFICE /AS OF 0830Z/. TEMPS ARE HOVERING AROUND 32F SO ANTICIPATE
SOME SLICK SPOTS ON SECONDARY AND ELEVATED ROADWAYS THIS MORNING.
WINTER WEATHER ADVISORY FOR CULLMAN/MARSHALL/DEKALB/JACKSON COUNTIES
AND FRANKLIN COUNTY IN TENNESSEE WILL REMAIN IN EFFECT THROUGH 9AM.
THE BACK EDGE OF THE SNOW...SUPPORTED BY RADAR AND COOLER CLOUD
TOPS ON IR SATL...IS QUICKLY MOVING ACROSS NORTHWEST ALABAMA AT THIS
TIME. THE SNOW WILL END AROUND HUNTSVILLE BTWN 10-12Z AND ACROSS THE
EASTERN COUNTIES BTWN 12-14Z...WITH ADDITIONAL ACCUMULATIONS OF LESS
THAN 1/2 INCH. DECREASING CLOUDS WILL QUICKLY FOLLOW THE TAPERING
SNOWFALL WITH THE ENTIRE FORECAST AREA SEEING PLENTY OF SUNSHINE
THIS AFTN...THOUGH IT WILL BE CHILLY AS UNSEASONABLY COLD AIRMASS
KEEPS TEMPS FROM RISING MUCH ABOVE 40F.
HIGH PRESSURE WILL BE IN CONTROL ACROSS THE AREA THROUGH SUNDAY
AHEAD OF NEXT SYSTEM DEVELOPING OVER THE CENTRAL PLAINS. COLDEST
NIGHT OF THIS FALL SEASON WILL OCCUR TONIGHT WITH TEMPS FALLING TO
BTWN 20-25F.
MOISTURE WILL INCREASE ACROSS THE AREA LATE SUNDAY INTO SUNDAY NIGHT
AHEAD OF A DECAYING SFC FRONT. HOWEVER...STRONG ISENTROPIC ASCENT
COUPLED WITH NOSE OF 110KT UPR JET ORIENTED ALONG THE SFC FRONT WILL
SUPPORT LIGHT RAIN...INITIALLY ACROSS NW ALABAMA...AFTER MIDNIGHT
SUNDAY NIGHT. RAIN WILL SPREAD ACROSS THE ENTIRE AREA MONDAY MRNG...
EXITING THE AREA BY LATE MONDAY AFTN. IT WILL BE A COLD RAIN WITH
TEMPS STRUGGLING TO GET OUT OF THE MID/UPR 40S MONDAY. RAINFALL
AMOUNTS WILL GENERALLY BE LIGHT AS MOISTURE IS RATHER LIMITED WITH
THIS SYSTEM. EXPECT GENERAL AMOUNTS BETWEEN 1/10 TO 1/4 INCH.
PROGRESSIVE LONGWAVE PATTERN WILL BRING A MUCH STRONGER SYSTEM TO
THE REGION TUESDAY/WEDNESDAY. 00Z/GFS AND ECMWF IN GOOD AGREEMENT
SHOWING DEEPENING SFC LOW OVER OK/KS BY 00Z/WED WITH WIDESPREAD
PRECIP SPREADING ACROSS THE SOUTHEAST REGION ALONG PRE-FRONTAL
TROUGH AND SFC WARM FRONT THAT WILL EXTEND SOUTHEAST FROM THE MAIN
LOW CENTER. THE LOW IS EXPECTED TO TRACK QUICKLY NORTHEAST REACHING
THE OHIO VALLEY/ERN GREAT LAKES BY WEDNESDAY AFTN. A COLD FRONT WILL
CROSS THE TN VALLEY WEDNESDAY...ENDING PRECIP AND BRINGING
COLDER/DRIER AIR TO THE AREA. STRONG UPR LVL DYNAMICS/KINEMATICS
COUPLED WITH DEEP MOISTURE SUPPORTS THE THREAT OF HEAVY RAIN...
ESPECIALLY IN THE VICINITY OF THE WARM FRONT. INSTABILITY APPEARS
RATHER WEAK THUS LEFT THUNDER OUT OF FCST AT THIS TIME...THOUGH
COULD NOT RULE OUT AN ISOLD TSTM ALONG/AHEAD OF COLD FRONT/DRYLINE
LATE TUESDAY AFTN/EVENING.
HIGH PRESSURE WILL BUILD BACK OVER THE AREA THURSDAY BUT WILL BE
SHORT-LIVED AS A WEAK "CLIPPER-LIKE" SYSTEM MOVES ACROSS THE AREA
FRIDAY BRINGING JUST A CHANCE OF LIGHT RAIN BY THE END OF THE WORK
WEEK INTO THE EARLY PART OF NEXT WEEKEND. AFTER ABOVE NORMAL TEMPS
TUESDAY INTO EARLY WEDNESDAY...TEMPS WILL COOL BACK CLOSE TO OR
SLIGHTLY BELOW NORMAL THU AND FRI. NADLER.83
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
007
