FXUS61 KILN 292347
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
647 PM EST SUN NOV 29 2009
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE REGION TONIGHT BRINGING RAIN
SHOWERS. HIGH PRESSURE WILL THEN BUILD INTO THE AREA LATE MONDAY
INTO TUESDAY....BEFORE A MORE AGGRESSIVE FRONTAL SYSTEM APPROACHES
BY MID WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TIMING BETWEEN SREF AND GFS SIMILAR WITH THE FROPA OVERNIGHT...
WITH GFS MORE AGGRESSIVE WITH THE LIFT AND MORE WIDESPREAD WITH THE
PRECIPITATION THIS EVENING AND OVERNIGHT...LIKELY DUE TO A GREATER
ENHANCEMENT OF THE LLJ AND LL CONVERGENCE OVERNIGHT. THOUGHT IS THAT
NAM IS TOO QUICK AND NOT AGGRESSIVE ENOUGH WITH THE LIFT. WHILE
POST FRONTAL PRECIP EXPECTED...SHOULD BE A PRETTY SHARP DROP OFF
AS DRY AIR EVENTUALLY WORKS IN. PRECIP SHOULD END IN ALL BUT THE
FAR SOUTH AND EAST BY 12Z...WITH FRONT WELL TO THE EAST BY THAT
TIME.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
HAVE TAKEN HIGH TEMPS DOWN A LITTLE FOR MONDAY...AS NW FLOW WORKS
IN. AGAIN STUCK CLOSER TO MAV MOS RATHER THAN NAM NUMBERS. A
QUICKLY MOVING S/WV PUSHES THROUGH MON NIGHT ACROSS THE LOWER
GREAT LAKES...SO HAVE CONTINUED THE SLIGHT CHANCE FOR SHSN IN THE
FAR NORTH.
RIDGING THEN BUILDS IN FOR TUE..BUT AS AGGRESSIVE SPLIT FLOW
PATTERN DEVELOPS IN THE SOUTHERN PLAINS AND NORTHERN
PLAINS...HIGH WILL PUSH PRETTY QUICKLY EAST AHEAD OF THE SOUTHERN
LOW.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
IN SPLIT FLOW PATTERN SOUTHERN STREAM UPPER LOW OVER TEXAS TO LIFT
NE INTO THE LOWER OHIO VALLEY ON WEDNESDAY AND THEN LIFT INTO THE
OHIO VALLEY WED NIGHT AND MERGE WITH FLOW AHD OF A DIGGING LONG WAVE
TROF. OPERATIONAL NUMERICAL MODEL SOLNS AND SREF MEAN TRENDING A LTL
SLOWER WITH THIS SYSTEM. SO THEREFORE HAVE HELD OFF RAIN UNTIL WED
AFTN WITH PRECIP SPREADING IN FROM THE SOUTH. WITH ASSOCIATED SFC
WAVE TRACKING INTO THE UPR OHIO VALLEY WED NIGHT HAVE INCREASED POPS
TO LKLY ACRS THE SOUTHEAST. ALSO...AS COLDER AIR FUNNELS INTO THE
REGION BEHIND THE LOW EXPECT A CHANGE OVER TO SNOW. WITH MOISTURE
LINGERING AND DIGGING UPR TROF...THIS MAY BE THE FIRST ACCUMULATING
SNOW OF THE SEASON IN MANY LOCATIONS.
DEEP UPPER LEVEL TROF TO SETTLE INTO THE GREAT LAKES ON THURSDAY
WITH CONSIDERABLY COLDER TEMPS EXPECTED. SNOW SHOWERS TO CONTINUE
WITH LAKE ENHANCED SNOW SHOWERS LIKELY LIKELY ACRS W CENTRAL OHIO
WITH FAVORABLE FETCH OFF LAKE MI. WL END ANY MENTION OF SNOW SHOWERS
FRIDAY AS SFC RIDGING BUILDS INTO THE OHIO VLY.
SOLNS SHOW A LARGE DIVERGENCE NEXT WEEKEND WITH ECMWF MAINTAINING THE
UPPER LOW OVER THE GREAT LAKES WHILE THE GFS IS MORE PROGRESSIVE. WL
FOLLOW SOLN CLOSER TO ECMWF WITH CONTD COLD TEMPERATURE BUT DRY
CONDITIONS WITH SNOW SHOWERS EXPECTED TO REMAIN NORTH OF ILN/S FA.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A COLD FRONT WILL MOVE ACROSS THE TAF SITES BETWEEN 05Z AND 07Z.
SHOWERS WILL ACCOMPANY THE FRONT...BUT SHOULD TAPER OFF ABOUT 2 TO
3 HOURS AFTER FRONTAL PASSAGE. BIGGEST CONCERN OVERNIGHT INTO
MONDAY MORNING WILL BE THE POTENTIAL FOR IFR CIGS. UPSTREAM
OBSERVATIONS WERE INDICATING IFR CIGS ALONG AND BEHIND THE
FRONT...AND MOST MODEL SOUNDINGS SUPPORT THIS. THUS...HAVE PLACED
A 3 TO 4 HOUR PERIOD OF IFR CIGS AT THE TAF SITES. WILL HAVE TO
MONITOR TRENDS SHOULD IFR CONDITIONS LAST LONGER INTO MONDAY MORNING.
OTHERWISE...A SFC RIDGE OF HIGH PRESSURE WILL BUILD INTO THE OHIO
VALLEY ON MONDAY. MVFR CIGS WILL LIFT TO VFR BETWEEN 16Z AND 18Z.
AN UPPER LEVEL WX DISTURBANCE AND ASSOCIATED SFC TROF IS FORECAST
TO MOVE ACROSS THE LOWER GREAT LAKES MONDAY NIGHT. PRECIPITATION
ASSOCIATED WITH THIS FEATURE IS EXPECTED TO REMAIN MAINLY NORTH OF
THE TAF SITES ATTM.
OUTLOOK...MVFR/IFR CIGS/VSBYS POSSIBLE WITH RAIN AND SNOW SHOWERS
WEDNESDAY NIGHT INTO THURSDAY. MVFR CIGS POSSIBLE ON FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...JDR
SHORT TERM...JDR
LONG TERM...AR
AVIATION...HICKMAN
