000
FXUS63 KIND 280447
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1145 PM EST MON DEC 27 2010
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE OVER THE OHIO AND TENNESSEE VALLEY WILL KEEP OUR
WEATHER QUIET AS IT MOVES ON TO THE EAST. A SOUTHERLY FLOW ON THE
BACK SIDE OF THIS HIGH WILL ALLOW TEMPERATURES TO BEGIN WARMING BY
MID WEEK. PRECIPITATION WILL BEGIN BY MIDWEEK. A COLD FRONT WILL
MOVE ACROSS OUR REGION EARLY SATURDAY BRINGING AN END TO THE RAIN
AND A RETURN TO SLIGHTLY BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /TONIGHT/...
EVEN THOUGH HIGH PRESSURE WILL DOMINATE OUR WEATHER. LOTS OF STRATUS
REMAIN. SOUNDINGS INDICATE THIS STRATUS IS TRAPPED UNDER A LOW LEVEL
INVERSION. MODELS STRENGTHEN THIS INVERSION SOME OVERNIGHT AND GIVEN
THAT THERE IS STILL LOTS OF STRATUS UPSTREAM WILL PLAY UP CLOUDS
MORE WITH THIS FORECAST. THESE CLOUDS MAY HOLD UP LOW TEMPERATURES
TONIGHT SO WILL LEAN CLOSER TO WARMER MET TEMPERATURES.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
FORECAST FOCUS IS ON PRECIPITATION CHANCES WEDNESDAY AND
WEDNESDAY NIGHT AS WELL AS PRECIP TYPE DURING THIS TIME. MODELS IN
DECENT AGREEMENT SO WILL USE A BLEND.
FOR TUESDAY SOME STRATUS WILL PROBABLY REMAIN AT LEAST OVER NORTHERN
AND CENTRAL SECTIONS UNTIL LATE TUESDAY AS MODELS MAINTAIN A LOW
LEVEL INVERSION OVER THE SNOW FIELDS. RATHER QUIET WEATHER WILL BE
THE RULE TUESDAY NIGHT AND EARLY WEDNESDAY AS SOUTHERLY FLOW
INCREASES.
UPPER FORCING ARRIVES AFTER 0Z THU IN THE WAY OF Q VECTOR
CONVERGENCE. NOT MUCH IN THE WAY OF FRONTOGENESIS BUT THERE IS
DECENT ISENTROPIC FORCING DURING THE OVERNIGHT HOURS. THE ISENTROPIC
LIFT LOOKS LIKE IT ARRIVES IN THE SOUTHWEST PRIOR TO 0Z THURSDAY /IN
THE GFS...CLOSE BUT PERHAPS NOT QUITE HERE AT THAT TIME IN THE NAM/
SO HAVE ADDED A SLIGHT CHANCE THERE IN THE AFTERNOON. PROFILES WILL
BE WARM ENOUGH BY THAT TIME FOR RAIN. FOR WEDNESDAY NIGHT GIVEN THE
FORCING PREVIOUSLY MENTIONED HAVE INCREASED POPS TO HIGH CHANCE IN
THE SOUTHWEST AND LOWER CHANCES TO THE NORTHEAST IN LINE WITH
PROXIMITY TO THE BEST FORCING. LOOKING AT SURFACE TEMPERATURES AND
FORECAST SOUNDINGS IT APPEARS THERE IS A CHANCE FOR SOME FREEZING
RAIN IN ABOUT THE NORTHEAST HALF OF THE AREA.
FOR TEMPERATURES TUESDAY THROUGH WEDNESDAY NIGHT STUCK WITH A MODEL
CONSENSUS. WEDNESDAY NIGHT STAYED CLOSER TO THE GFS TEMPERATURES AS
THIS MATCHED EXPECTED PROGRESSION OF WARM ADVECTION BEST.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL BE ALONG THE CAROLINA COAST EARLY IN THE PERIOD
AND THIS WILL PRODUCE A MILD MOIST FLOW OF AIR FROM THE GULF OF
MEXICO. MODELS INDICATE THERE MAY BE A LUL IN PRECIPITATION ONCE IT
MOVES OUT EARLY THURSDAY AS AN UPPER RIDGE BUILDS ACROSS OUR REGION.
THE COMBINATION OF MELTING SNOW AND MOIST SOUTHERLY FLOW SHOULD
PRODUCE AREAS OF FOG THURSDAY INTO FRIDAY.
A STRONG COLD FRONT WILL MOVE THROUGH OUR REGION LATE FRIDAY NIGHT
OR VERY EARLY SATURDAY PER MODEL CONSENSUS. SOUNDINGS SHOW SOME
INSTABILITY ALOFT SO WILL MENTION THUNDER MOST AREAS FRIDAY NIGHT.
JUST ABOUT EVERY MODEL ENDS PRECIPITATION BY 18Z SATURDAY AS DRY
SLOT OVERSPREADS OUR REGION. BELIEVE HPC POPS MAY BE TOO HIGH.
WILL MENTION TRACE AMOUNTS INTO SATURDAY EVENING AND THEN GO DRY ON
SUNDAY.
MODELS ROTATE A STRONG UPPER TROUGH FROM THE NORTHERN PLAINS TO THE
NORTHERN GREAT LAKES OVER THE WEEKEND. AFTER THE WEEKEND A MORE
ZONAL FLOW SETS UP ACROSS THE U.S. BRINGING US QUIET WEATHER AND
NEAR NORMAL TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 280600Z TAF ISSUANCE/...
AREA OF CEILINGS FROM 007-012 ACROSS THE AREA EXTENDING BACK INTO
ILLINOIS. SATELLITE LOOPS SHOW SOME SLIGHT EASTWARD PROGRESSION OF
THE CLEARING LINE...BUT NOT MUCH. THIS EVENING/S UPPER AIR OUT OF
CENTRAL ILLINOIS SHOWS A VERY SHARP INVERSION ABOVE ABOUT 015...SO
THINK CEILINGS WILL HOLD OVERNIGHT INTO TUESDAY MORNING. LOW
CONFIDENCE ON JUST HOW FAST IFR CEILINGS WILL LIFT TUESDAY
MORNING...WITH MODEL DATA SUGGESTING AS EARLY AS SUNRISE
TUESDAY...OR AS LATE AS MIDDAY. GIVEN THE SHARP INVERSION WHICH
SHOULD PREVENT MUCH MIXING...WILL LEAN MORE TOWARDS THE PESSIMISTIC
SIDE WITH IFR CEILINGS LIFTING INTO AN MVFR DECK 281600Z-281800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM....JH
AVIATION...JAS
