HAMweather.com Area Forecast Discussion for County Warning Area OHX

Thu, 16 Feb 2012 05:36:00 GMT
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NASHVILLE TN
1136 PM CST WED FEB 15 2012

.UPDATE...FOR 06Z AVAITION DISCUSSION.

.AVIATION...06Z AVIATION DISCUSSION.
UNCERTAINTIES...VFR TO IFR/LIFR CEILING PROGRESSION...LIGHT SHWR IMPACTS...
 LOW LEVEL WIND SHEAR POTENTIAL. LIGHT RAINFALL WILL NOT INHIBIT
OVERALL VSBYS THRU 16/19Z. WITH STRONG SLY/SWLY LOW LEVEL JET DYNAMICS
AT 16/06Z...EXPECTED THRU 16/15Z...CONTINUE LOW LEVEL MAINLY SPEED
SHEAR LOWEST 2KFT. SFC COLD FRONTAL PASSAGE E OF AREA BY 16/18Z...HOW
LONG IFR CEILINGS WILL BE AROUND...ESPECIALLY CSV...STILL IN QUESTION.
CEILING ERROSION BNA BY AROUND 16/18Z  A IFR TO MVFR CEILINGS
TRANSITION CSV 16/19Z...WITH 17/00Z CSV CEILING ERROSION.

.PREV DISCUSSION.../ISSUED 654 PM CST WED FEB 15 2012/

UPDATE...
BROKEN SHOWER ACTIVITY COVERING MUCH OF THE WESTERN TWO THIRDS OF
THE MID STATE. THIS ACTIVITY EXTENDS WESTWARD THROUGH WESTERN TN
AND INTO EASTERN AR. A FEW LIGHTNING STRIKES ARE NOTED OVER
SOUTHWESTERN TN AND POINTS WEST. DEW POINTS WILL CONTINUE TO SLOWLY
TREND UPWARD OVERNIGHT SO THE ISOL T THAT IS CURRENTLY IN THE
FORECAST LOOKS TO BE OK....ESPECIALLY ACROSS OUR SOUTHERN ZONES.

CANT REALLY FIND A REASON TO UPDATE THE FCST AT THIS POINT. LOOKS
AS THOUGH THE CATEGORICAL POPS WILL HOLD AS PRECIP EXTENDS WELL TO
OUR WEST. 

DEW POINTS ARE STILL IN THE LOWER 30S PLATEAU. HOWEVER...HIGHER DEW
POINTS ARE NOTED TO THE SOUTH. 

NO UPDATE NEEDED FOR NOW.

PREV DISCUSSION.../ISSUED 546 PM CST WED FEB 15 2012/

UPDATE...FOR 00Z AVIATION DISCUSSION.

AVIATION...00Z AVIATION DISCUSSION.
UNCERTAINTIES...VFR TO IFR/LIFR CEILING PROGRESSION...LIGHT SHWR IMPACTS...
AND LOW LEVEL WIND SHEAR POTENTIAL. PER REASONING BELOW...LIGHT RAINFALL
SHOULD NOT OVERALL INHIBIT VSBYS UNTIL 16/07Z-16/09Z TIME FRAME. WITH STRONG
SLY/SWLY LOW LEVEL JET DYNAMICS IN PLACE DURING THE 16/06Z-16/15Z TIME FRAME
.EXPECT AT LEAST SOME SPEED SHEAR IN LOWEST 2KFT. SFC COLD FRONTAL PASSAGE
SHOULD BE E OF MID STATE BY 16/18Z...BUT HOW LONG IFR CEILINGS WILL BE AROUND
IS STILL IN QUESTION. WILL GENERALLY TREND TO CEILING ERROSION BNA BY AROUND
16/18Z AND A TRANSITION FROM IFR TO MVFR CEILINGS CSV BY 16/19Z.

PREV DISCUSSION... /ISSUED 320 PM CST WED FEB 15 2012/ 

DISCUSSION...HAD SOME SPRINKLES EARLY THIS MORNING BUT THOSE GAVE
WAY TO PARTLY SUNNY SKIES FOR THE BULK OF THE DAY. A FEW LIGHT
SHOWERS WERE MOVING INTO MIDDLE TN FROM THE WEST AT 21Z. IT/S NOT
NEARLY AS COOL TODAY WITH TEMPS UP 15 TO 20 DEGREES MOST AREAS.

OVERALL IT LOOKS LIKE A PROGRESSIVE PATTERN FOR THE WEEK AHEAD
WITH POTENTIALLY 3 SYSTEMS TO IMPACT US. THE FIRST WILL BE
TONIGHT WITH THE OTHER 2 POTENTIALLY SATURDAY NIGHT AND NEXT
TUE/WED.

THE FIRST SYSTEM IS A WEAK H5 LOW OVER WESTERN OK TODAY. MODELS
CONSISTENTLY WEAKEN THE LOW AND MOVE IT QUICKLY EASTWARD INTO THE
OH VALLEY BY TOMORROW. MOISTURE INCREASING TO OUR WEST TODAY WILL
OVERSPREAD THE REGION TONIGHT AND THEN QUICKLY EXIT THE REGION
TOMORROW MORNING. LOOKS LIKE A HI POP BUT LOW QPF SCENARIO AS MOST
AREAS SHOULD RECEIVE LESS THAN 1/3 INCH. SOME PRECIP MAY LINGER
EARLY TOMORROW ON THE PLATEAU. ASSOCIATED WEAK COLD FRONT WILL
SWEEP FROM W TO E ACROSS THE AREA 12Z TO 18Z THURSDAY.

H5 FLOW WILL BE MAINLY ZONAL THUR/FRI. A BIT COOLER THURSDAY NIGHT
AND FRIDAY BEHIND THE FRONT BUT TEMPS WILL REMAIN ABOVE THE
SEASONAL NORMS.

H5 LOW OVER CA TODAY WILL DROP INTO NRN MEXICO FRIDAY THEN WEAKEN
AND MOVE NORTHEAST. GFS/ECMWF DIFFER ON THE AMOUNT OF IMPACT IN
MID TN... WITH THE GFS BEING WETTER AND THE ECMWF KEEPING MUCH OF
THE MOISTURE TO OUR SOUTHEAST. WILL LEAN A BIT TOWARD THE GFS
BASED ON SEASONAL CLIMATOLOGY. EITHER WAY...STILL DON/T EXPECT
THIS TO BE A BIG PRECIP MAKER. WILL INCLUDE CHANCE FOR MIXED
PRECIP ACROSS THE NORTH AND PLATEAU LATE SAT NIGHT AND EARLY
SUNDAY AS COLD AIR ARRIVES AT TAIL END OF PRECIP.

SUNDAY THROUGH WEDNESDAY... SHORT WAVE RIDGE WITH FAIR WEATHER
SUNDAY AFTERNOON THROUGH MONDAY...THEN THE THIRD SYSTEM WILL
APPROACH US FROM THE SOUTHWEST TUE/WED. GFS IS WETTER AND A
LITTLE SLOWER THAN THE ECMWF BUT BOTH SCENARIOS WARRANT INCREASING
CHANCES FOR PRECIP TUE/WED. BOTH MODELS PASS THE SFC LOW TO OUR
NORTHWEST SO THIS SHOULD BE A FAIRLY MILD SYSTEM...IE...RAIN BUT
NO SNOW. LV

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.