FXUS64 KOHX 231622 AAA
AFDOHX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NASHVILLE TN
1022 AM CST WED DEC 23 2009

.UPDATE...
SURFACE ANALYSIS AT 14Z SHOWED LOW PRESSURE ORGANIZING OVER NE KS. A 
RIDGE OF HIGH PRESSURE EXTENDED FROM WESTERN GREAT LAKES INTO THE 
MID ATLANTIC STATES AND INTO THE SE. 

AT 850 MB...A NORTHWARD SURGE OF MOISTURE WAS OCCURRING ALONG A
LOW LEVEL JET...EXTENDING FROM E TX AND W GULF OF MEXICO...AS FAR
N AS E KS AND W MO. CLOSED 500 MB LOW WAS ON THE AZ...NM BORDER...
WITH A RIDGE AXIS EXTENDING FM THE SE US TO MN.

VERY LITTLE INCREASE IN PRECIP EFFICIENCY VALUES EXPECTED THIS
AFTERNOON ACROSS THE AREA. ALSO...IT APPEARS THERE WILL BE LITTLE
IN THE WAY OF ISENTROPIC LIFTING TODAY. THAT...COMBINED WITH A SURFACE
RIDGE AXIS THAT WILL MOVE VERY LITTLE TO THE E TODAY...MAKES ME
BELIEVE THAT CURRENT FORECAST POPS FOR TODAY ARE TOO HIGH OVER ALL
BUT PERHAPS THE FAR W SECTIONS.

WILL THEREFORE LOWER POPS A BIT FOR REST OF TODAY...AND REMOVE CHANCES
OF PRECIP FOR PLATEAU AREA ALL TOGETHER. WILL ALSO RAISE MAX TEMPS
FOR A COUPLE OF DEGREES.

UPDATED FORECASTS WILL BE ISSUE SHORTLY.

&&

.PREV DISCUSSION... /ISSUED 336 AM CST WED DEC 23 2009/ 

DISCUSSION...
FORECAST REASONING WILL BE BASED ON A LEAN TOWARD THE EURO MODEL 
SOLUTION FOR THE FORECAST PERIOD UNLESS OTHERWISE NOTED.

CURRENTLY...CLOUDY SKIES ACROSS THE MID STATE WITH TEMPS IN THE
LOWER TO MID 40S TO UPPER 30S...DEWPOINTS SPANNING THE 30S...
AND LIGHT SE WINDS. LIGHT RAINFALL APPROACHING THE TN RIVER VALLEY. 
SFC GULF MOISTURE FETCH IN PLACE WITH STATIONARY FRONT POSITIONED TO
OUR NW. WEAK UPPER LEVEL RIDGING SE TO NW ACROSS THE MID STATE.

FORECAST QUANDARIES...STRONG STORM SYSTEM STILL EVIDENT ON WATER 
VAPOR IMAGERY TURNING ACROSS THE SW U.S. THIS STRONG STORM SYSTEM 
WILL BE MAIN WEATHER PLAYER FOR THE MID STATE THIS FORECAST PERIOD. 
LATEST MODEL GUIDANCE STILL SHOWS THAT SYSTEM WILL PHASE WITH 
NORTHERN STREAM ENERGY BY LATE THU...RESULTING IN POTENTIALLY 
POWERFUL STORM SYSTEM OVER THE ERN 1/2 U.S. THRU EARLY NEXT WEEK.

SLY FLOW WILL STRENGTHEN STEADILY THRU THU AS SFC LOW MOVES INTO
N MO...AS UPPER LEVEL FLOW BECOMES PREDOMINATELY SWLY PER UPPER
LEVEL LOW ACROSS THE ERN PLAINS OF NM. WILL GO CLOSE TO NAM MOS
HIGHS THRU FRI. DEEP MOISTURE WILL INCREASE...BUT WITH LOW LEVEL
FLOW FROM THE SE...BOUNDARY LAYER WILL CONTINUE TO REMAIN PRETTY
DRY THRU 12Z THU...HOWEVER DO BELIEVE THAT MOST LOCATIONS WILL
EXPERIENCE SOME LIGHT RAINFALL ACROSS THE MID STATE. WILL CONTINUE
FORECAST TREND OF A W-E POP GRADIENT TODAY THRU 12Z THU....WITH
CATEGORICAL COVERAGE EXPECTED LATE THU INTO THU NGT...AS FRONT
EXPECTED TO OCCLUDE AND STRETCH FROM NEAR MOBILE BAY, AL...INTO
THE RED RIVER VALLEY REGION OF ND. A SIGNIFICANT UPPER LEVEL
TROUGH WILL DEVELOP ACROSS THE CNTRL U.S IN ASSOCIATION WITH
AN DEEPENING UPPER LEVEL LOW ACROSS THE CNTRL PLAINS...PROVIDING A
CONTINUANCE IN SWLY FLOW ALOFT. SHOWALTERS VALUES APPROACH ZERO
LATE THU AFTERNOON INTO THU NIGHT...SO ISOLATED TSTMS
POSSIBLE...AND CAN NOT RULE OUT THE POSSIBILITY OF A SHALLOW
CONVECTIVE LINE DEVELOPING ALONG AND AHEAD OF THE FRONT....AS IT
MOVES W TO E ACROSS THE MID STATE THU NIGHT.

GUIDANCE AND LMRFC GRAPHICS DEPICTING AREAL TOTAL QPF AMOUNTS WILL
GENERALLY RANGE FROM ONE INCH W TO AROUND ONE QUARTER OF AN INCH
ACROSS THE CUMBERLAND PLATEAU REGION. HOWEVER...WITH ISOLATED TSTMS
IN THE FORECAST FOR LATE THU AFTERNOON THRU THU NIGHT...ISOLATED
LOCATIONS COULD SEE HIGHER AMOUNTS. DO NOT BELIEVE THAT WE WILL
SEE THE HEAVY RAINFALL POTENTIAL THREAT THAT OUR NEIGHBORS MIGHT
EXPERIENCE TO OUR S.

MAIN FORECAST QUANDARY CENTERS AROUND THE POTENTIAL ISSUANCE OF A
WIND ADVISORY FOR THE MID STATE ON THU. AS STORM DEEPENS TO OUR 
W...WINDS WILL STRENGTHEN THROUGH THE DAY THU. GFS/EURO ARE THE 
STRONGEST...60+ KTS AT 925 MB OVER PARTS OF W PORTIONS OF THE MID
STATE STARTING AS EARLY AS 15Z THU. THE POTENTIAL EXIST FOR 25+ MPH 
SUSTAINED WINDS AND GUSTS IN THE 40-45 MPH RANGE FROM 15Z THU TO
06Z FRI. IN AGREEMENT WITH MY NEIGHBORS TO MY W AND S ON THIS 
REASONING. THUS..WILL HIGHLIGHT WIND THREAT WITH A WIND ADVISORY
ISSUANCE FROM LATE THU MORNING THRU THU EVENING.

UPPER LOW WILL THEN BASICALLY SIT AND SPIN OVER THE GREAT LAKES 
THROUGH AT LEAST EARLY NEXT WEEK. THIS WILL LEAD TO A PERIOD OF MUCH 
COOLER TEMPS...A TRANSITION FROM CLOUDY SKIES TO PARTLY CLOUDY 
SKIES...AND CHANCE FOR LIGHT PRECIP MAINLY OVER THE PLATEAU THRU
SAT NIGHT...OF WHICH A RAIN/SNOW MIXTURE WILL BE POSSIBLE SAT AND
LIGHT SNOWFALL SAT NIGHT.

THANKS FOR INPUT HUN...LMK...AND JKL

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM THURSDAY TO MIDNIGHT CST THURSDAY NIGHT 
FOR TNZ005>011-022>034-056>066-075-077>080-093>095.

&&

$$
STEIGERWALDT