774
FXUS63 KIWX 071732
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1232 PM EST SAT NOV 7 2009
AVIATION
CLEAR SKIES WITH GUSTY SW WINDS THIS AFTERNOON AS WEAK FRONTAL
BOUNDARY APPROACHES ABSENT OF CLOUDS DUE TO VERY DRY COLUMN ABOVE
SHALLOW LLEVEL MOISTURE. WINDS DROPPING OFF OVERNIGHT UNDER CLEAR
SKIES WILL ALLOW FOR GENERATION OF FOG DURING MORNING HOURS
CURRENTLY PROGGED MVFR BUT POTENTIAL CERTAINLY EXISTS FOR VIS TO
DROP TO IFR. VIS RESTRICTIONS LIFT WITH ADDITION OF SUNSHINE
SUNDAY MORNING RETURNING TERMINALS TO VFR CONDS AND LIGHTER SE
WINDS 5-10KTS.
PREV DISCUSSION... /ISSUED 700 AM EST SAT NOV 7 2009/
SHORT TERM...
TODAY THROUGH SUNDAY NIGHT. LITTLE CHANGE IN SHORT TERM. RAISED
TEMPS A FEW DEGREES AS 1000-850MB THERMAL AXIS FM CNTL PLAINS INTO
WI TO LAY ACROSS FA LTR TODAY AS FRONTALYTIC ZONE ACRS THE NRN
PLAINS MOVES TOWARD SOUTHERN GREAT LAKES WHILE BEING OVERTAKEN BY
BIFURCATING SFC HIGH MOVES QUICKLY OFF NRN ROCKIES PLATEAU AND
INTO SWRN GRTLKS BY THIS EVENING. SFC WIND GUSTS TO AROUND 30 MPH
ESPECIALLY LATE AM/ERLY AFTN AT HEIGHT OF MIXING DEPTH AND PRIOR
TO BULK OF LLVL JET AXIS SLIDING EWD. RAISED TEMPS SLIGHTLY ALSO
OVERNIGHT WITH LITTLE AIRMASS EXCHANGE. SPLIT MAV/MET DIFFERENCE
AT KBEH WHERE DTC/LAND BREEZE MAY SET-UP BY DAYBREAK SUNDAY
ALLOWING FOR COLD AIR DRAINAGE TOWARD SHORELINE/METAR SITE. SRLY
FLOW BECOMES ESTABLISHED AHEAD OF SERN CO LOW EJECTING INTO PLAINS
WITH BAJA SYSTEM AT LEAST PROVIDING A LITTLE BUCKLE IN UPSTREAM
FLOW...DEVOID IN DY1 SYSTEM.
LONG TERM...
MONDAY THROUGH FRIDAY...THE MAIN CHALLENGE THIS PERIOD CONTINUES TO
BE THE TIMING OF SHORT WAVE TROFS MOVING THROUGH THE LONG WAVE
PATTERN. THIS IS ESPECIALLY TRUE DURING THE LATTER HALF OF THE WEEK
WHEN THERE IS A SIGNIFICANT MODEL DIVERGENCE AMONG GFS...ECMWF AND
CANADIAN GEM SOLUTIONS. FOR THIS PACKAGE...SELECTED A GENERAL NCEP
MODEL BLEND...ALTHOUGH CONFIDENCE LATE IN THE PERIOD WAS TOO LOW TO
MAKE ANY CHANGES. THE GFS ANALOGS WERE STILL SHOWING A STRONG
SIGNAL THAT INCLUDES A BROAD TROF OVER THE WESTERN CONUS WITH
RIDGING DOWNSTREAM. THIS WOULD IMPLY SHORTWAVES EJECTING OUT OF THE
MAIN TROF WOULD HAVE LIMITED COLD AIR ADVECTION DOWNSTREAM. THE
OVERALL MILD PATTERN SHOULD PERSIST THROUGH THE PERIOD...EXCEPT FOR
BRIEFLY COOLER CONDITIONS DURING THE MIDDLE OF THE WEEK BEHIND THE
COLD FRONT. THE ONGOING TIMING OF THE INITIAL SHORTWAVE AND
ASSOCIATED FRONT MONDAY NIGHT/EARLY TUESDAY STILL APPEARS ON TRACK.
KEPT LOW CHANCES FOR RAIN GIVEN LIMITED MOISTURE AND WEAK DYNAMICS.
LOWERED LOWS A FEW DEGREES AFTER THIS SYSTEM PASSES TUESDAY NIGHT
AND WEDNESDAY NIGHT.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ043-
046.
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...LUD
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page