FXUS64 KMRX 230815
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
315 AM EST WED DEC 23 2009
.SHORT TERM (TODAY AND TONIGHT)...HIGH PRESSURE ACROSS THE AREA
SHOULD BRING A DRY DAY TODAY. WILL SEE SOME HIGH CLOUDINESS TODAY
AHEAD OF NEXT SYSTEM UPSTREAM. THE DRIER AIR IN THE LOW LEVELS
SHOULD HOLD OFF THE HIGHER CHANCES FOR PRECIPITATION UNTIL
THURSDAY...BUT WILL CONTINUE THE SLIGHT CHANCE POPS FOR JUST THE
WESTERN PORTIONS OF THE CWA FOR TONIGHT. GUIDANCE TEMPERATURES
LOOKED REASONABLE...SO DIDN''T STRAY TOO FAR FOR TODAY AND TONIGHT.
.LONG TERM (THURSDAY THROUGH TUESDAY)...MODELS ARE IN GOOD AGREEMENT
THROUGH THE EXTENDED PERIOD...AND REVEAL A HIGHLY AMPLIFIED UPPER-
LEVEL PATTERN ACROSS THE EASTERN HALF OF THE NATION THROUGH EARLY
NEXT WEEK. A STRONG LOW PRESSURE SYSTEM IS PROGGED TO STRENGTHEN
OVER THE OZARKS REGION ON THURSDAY...WITH A HIGHLY AMPLIFIED UPPER-
LEVEL TROUGH OVER THE PLAINS CAUSING ITS ASSOCIATED SURFACE LOW TO
LINGER AROUND THE MID MS RIVER VALLEY THROUGH FRIDAY. THE COLD FRONT
ASSOCIATED WITH THIS SYSTEM IS PROGGED TO MOVE INTO THE FORECAST
AREA AROUND 12Z ON FRIDAY MORNING...WITH WIDESPREAD RAIN SHOWERS
OCCURRING ALONG AND AHEAD OF IT. MODEL SOUNDINGS INDICATE A STRONG
SURFACE-BASED INVERSION OVER THE SOUTHERN APPALACHIAN REGION BY
THURSDAY NIGHT...WITH A STRONG VEERING WIND PROFILE THAT RAPIDLY
INCREASES WITH HEIGHT. THUS...IT APPEARS THAT THIS SYSTEM WILL HAVE
THE POTENTIAL TO PRODUCE ANOTHER HIGH-END WIND EVENT DUE TO MOUNTAIN
WAVES IN THE WESTERN FOOTHILLS OF THE MOUNTAINS (THE THIRD ONE THIS
MONTH). WITH THIS IN MIND...WILL PLAN TO ISSUE A HIGH WIND WATCH FOR
THE WESTERN FOOTHILLS FOR LATE THURSDAY AFTERNOON THROUGH FRIDAY
MORNING...AND WILL MENTION WIND GUSTS IN EXCESS OF 60 MPH (ALSO
THINK THAT MAXIMUM WIND GUSTS WILL LIKELY REACH INTO THE 80 TO 100
MPH RANGE IN THE FAVORED LOCATIONS).
ANOTHER CONCERN WITH THIS SYSTEM IS THE POSSIBILITY OF FLOODING...
ESPECIALLY IN THOSE AREAS THAT STILL HAVE A DECENT SNOW PACK (THE
MOUNTAINS AND SOUTHWEST VA). WHILE THE MODELS ONLY INDICATE BETWEEN
A HALF OF AN INCH TO AN INCH OF RAINFALL (DUE TO STRONG DOWNSLOPE
SOUTHEASTERLY WINDS ACROSS THE VALLEYS)...THE COMBINATION OF A GOOD
SNOW PACK AND A SATURATED GROUND MAY CONTRIBUTE TO SOME FLOODING
PROBLEMS. AFTER THE COLD FRONT MOVES THROUGH THE FORECAST AREA ON
FRIDAY MORNING...MODELS AGREE THAT PRECIP WILL QUICKLY EXIT THE
REGION AS AN EXTENSIVE DRY SLOT MOVES IN BEHIND THIS FRONT. THE
STRONGLY AMPLIFIED UPPER TROUGH WITH THIS SYSTEM IS PROGGED TO
DEEPEN FURTHER INTO A CUT-OFF LOW BY THE WEEKEND...AND LINGER AROUND
THE GREAT LAKES REGION THROUGH THE WEEKEND. MODELS AGREE THAT THIS
UPPER LOW WILL NOT HAVE A LOT OF MOISTURE ASSOCIATED WITH IT...SO
THINK THAT IT WILL BRING MOSTLY AN INCREASE IN CLOUDS BY SUNDAY OVER
THE NORTHERN HALF OF THE FORECAST AREA WITH POSSIBLY A FEW LIGHT
SNOW SHOWERS. HOWEVER...IT APPEARS THAT ONLY LIGHT ACCUMULATIONS
WOULD BE POSSIBLE ON SUNDAY...AND MAINLY ACROSS THE HIGHER
ELEVATIONS. ANOTHER SOUTHERN SYSTEM IS PROGGED TO DEVELOP IN THE
ACTIVE SOUTHERN JET STREAM FOR THE MIDDLE PART OF NEXT WEEK...BUT IT
APPEARS THAT ANY PRECIP WITH IT WILL WAIT UNTIL WEDNESDAY TO AFFECT
THE FORECAST AREA. AS FOR TEMPS...WILL TREND CLOSE TO THE GFS NUMBER
THROUGH THE EXTENDED PERIOD...WHICH ARE IN GOOD AGREEMENT WITH THE
ENSEMBLE MEANS.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 55 37 53 43 50 / 10 20 60 100 30
KNOXVILLE MCGHEE TYSON AIRPORT, TN 51 36 52 43 49 / 0 10 40 100 50
OAK RIDGE, TN 51 36 53 43 49 / 0 10 40 100 50
TRI CITIES AIRPORT, TN 47 29 50 38 48 / 0 10 30 100 70
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...HIGH WIND WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY MORNING
FOR THE FOLLOWING ZONES: BLOUNT SMOKY MOUNTAINS...COCKE
SMOKY MOUNTAINS...EAST POLK...JOHNSON...MCMINN...NW
BLOUNT...NORTH SEVIER...NORTHWEST CARTER...NORTHWEST
COCKE...NORTHWEST GREENE...NORTHWEST MONROE...SEVIER SMOKY
MOUNTAINS...SOUTHEAST CARTER...SOUTHEAST GREENE...SOUTHEAST
MONROE...UNICOI...WASHINGTON TN...WEST POLK.
VA...NONE.
&&
$$
GH/DMG
