FXUS63 KEAX 011735
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1135 AM CST TUE DEC 1 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
FCST CONCERN INVOLVES THE FUTURE TRACK OF UPPER SYSTEMS WELL TO THE
SW AND TO THE NW. UPPER TROUGH OVER ALBERTA AND NRN MONTANA WILL CONTINUE
TO DRIVE ESE WHILE AN UPPER LEVEL LOW BURIED OVER NRN MEXICO WILL
GRADUALLY GET A KICK TO THE ENE TODAY. MODELS HAVE VARIED A LITTLE THE
LAST FEW DAYS WITH THE TRACK OF THIS SYSTEM...AND HAVE OCCASIONALLY
THREATEN THE EXTREME SERN CWA WITH PRECIPITATION. LATEST 00Z RUNS
SUGGEST THAT THE PRECIPITATION CHCS FOR THE EXTREME SRN CWA ARE SMALL
AS THE UPPER LEVEL LOW TRACKS WELL TO THE SOUTH IN NRN LA/SRN ARK.
THIS KEEPS THE DEFORMATION ZONE TO THE SE OF THE CWA WITH THE ONLY
FORCING NOTED BEING ELEVATED FRONTOGENETICAL OVER THE SERN ONE THIRD
OF THE CWA. IF PRECIPITATION DOES OCCUR...HAVE SOME CONCERN ABOUT A
CHANGEOVER TO SNOW...BUT GIVEN THE PRECIPITATION WILL BE
LIGHT...DYNAMIC/DIABATIC COOLING PROCESSES WILL BE MINIMIZED. THESE
COOLING PROCESSES WILL BE NECESSARY GIVEN THAT THE AIR MASS BEING
ADVECTED SE INTO THE CWA TONIGHT IS NOT ESPECIALLY COLD. TEMPERATURES
ARE ONLY IN THE 20S AND 30S BEHIND THE FRONT IN MONTANA. HAVE TRIMMED
POPS SLIGHTLY FOR THE SE CORNER AND HAVE KEPT THEM IN THE LOW CHC
CATEGORY.
OTHERWISE...THE FIRE DANGER WILL INCREASE TODAY AS GUSTY AND DRY WEST
SOUTHWEST WINDS WILL PREVAIL. HOWEVER...RED FLAG CRITERIA WILL NOT BE MET.
CONTINUED TO GO A LITTLE ABOVE GUIDANCE FOR TODAY GIVEN BETTER
MIXING WITH THE DRY AND GUSTY WEST SOUTHWEST WINDS.
THE FRONT WILL CLEAR THE CWA BY TONIGHT AND WEDNESDAY WITH COOLER
TEMPERATURES. A COLD VORTEX WILL DROP INTO THE NRN PLAINS AND GREAT
LAKES REGION THURSDAY WITH A COUPLE OF SHORTWAVES RACING THROUGH THE
CWFA. AS THE UPPER LEVEL LOW DROPS INTO THE GREAT LAKES REGION ON
THURSDAY...COLDER AIR WILL CONTINUE TO FEED SOUTH INTO MISSOURI. THE
COLDER AND RELATIVELY MOIST AIR CIRCULATING AROUND THE COLD
VORTEX...IN COMBINATION WITH WEAK SHORTWAVES...WILL PROVIDE FOR A
THREAT OF SNOW FLURRIES...MAINLY FOR THE NRN CWFA.
DB
&&
.AVIATION...
FOR THE 18Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID
PERIOD. MAIN CONCERN FOR THE NEXT 6 HOURS IS FAIRLY STRONG SOUTH
SOUTHWESTERLY WINDS. A TIGHT PRESSURE GRADIENT WILL PERSIST OVER THE
AREA AHEAD OF FRONT THAT IS CURRENTLY POSITIONED FROM EASTERN
NEBRASKA THROUGH NORTHWEST KANSAS. THESE WINDS WILL DECREASE A BIT
LATER THIS AFTERNOON/EVENING AS THE PRESSURE GRADIENT WEAKENS. THE
FRONT WILL MOVE THROUGH THE SITES BETWEEN O4Z AND 06Z. WINDS WILL
SHIFT TO THE NORTH/NORTHWEST WITH INCREASING CLOUDS BEHIND THE FRONT.
FOR NOW WILL KEEP CIGS VFR AS SOUNDINGS STILL LOOK FAIRLY DRY.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
