FXUS63 KOAX 271911
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
211 PM CDT MON SEP 27 2010
.SHORT TERM...TONIGHT THROUGH THURSDAY.
A COUPLE OF FRONTAL PASSAGES WILL AFFECT THE FORECAST AREA DURING
THE SHORT TERM WITH THE MAIN STORM ACTIVITY OVER THE EAST COAST
AND BACK INTO THE GREAT LAKES. BASED ON THE ANTICIPATED RH
PROFILES...THESE FRONTS WILL PASS THROUGH DRY...THUS TEMPERATURES
AND WINDS WILL BE THE PRIMARY FORECAST CONCERNS.
AT MIDDAY...THE PRE-FRONTAL WINDSHIFT WAS APPROACHING KOFK...WITH
NORTHWEST WINDS THRU KONL AND TEMPS WARMING TO 75 TO 80 DEGREES
BEHIND THE TROF. BY 00Z...COOLER AIR WILL BE DROPPING TEMPERATURES
AND THE NORTH WINDS WILL KICK UP BEHIND THE WINDSHIFT. LATER
TONIGHT SFC HIGH PRES WILL BUILD IN...SFC WINDS WILL SETTLE DOWN
WITH COOLEST TEMPERATURES IN THE NORTH AND WESTERN CWA. THIS IS
WHERE DEWPOINTS WILL DROP THE MOST AND THE WINDS WILL BE LIGHTEST.
LOWS TUESDAY MORNING SHOULD BE IN THE MID 40S TO LOWER 50S. HIGH
TEMPERATURES TUESDAY SHOULD BE CLOSE TO NORMAL...MOSTLY FROM 69 TO
75.
SFC HIGH PRESSURE WILL GRADUALLY SLIDE TO THE EAST TUESDAY NIGHT
WITH RETURN SOUTH FLOW DEVELOPING. LOOK FOR LOWS IN THE 40S TO
LOWER 50S. WEDNESDAY...THE THERMAL RIDGE BUILDS IN AHEAD OF THE
NEXT FROPA WED WITH TEMPS WARMING INTO THE UPR 70S AND LOWER 80S.
ONCE AGAIN...THE NORTHWEST WINDS PICK UP WITH THE WINDSHIFT...BUT
DROP BACK DOWN OVERNIGHT AS HIGH PRES BUILDS IN. LOWS THURSDAY
MORNING SHOULD AGAIN BE IN THE 40S TO LOWER 50S.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY.
GFS TRENDS OF ITS LAST FEW RUNS HAVE COME MORE AROUND TO THE COOLER
ECMWF THROUGH THE WEEKEND AS BLOCKING ATLANTIC RIDGE APPEARS IT WILL
ALLOW STRONGER SHORT WAVE ENERGY TO DIG SWD ACROSS GREAT LAKES
REGION. THIS SHORTWV THEN MERGES WITH SERN U.S. ENERGY INTO A
LARGER EAST COAST TROUGH KEEPING ROCKY MOUNTAIN RIDGE MORE AMPLIFIED
AND CENTERED A BIT FARTHER WEST. THUS MORE BACKDOOR COOLING APPEARS
LIKELY...ESPECIALLY SAT AND SUNDAY...AND TEMPS WERE LOWERED TOWARD
MEX GUIDANCE...GENERALLY UPPER 60S. STILL SOME QUESTION ON HOW MUCH
OF THIS COOLING WILL ARRIVE BY FRIDAY AND HOW LONG IT WILL STICK
AROUND SINCE THE GFS HAD PERSISTENTLY SHOWN MUCH ABOVE NORMAL
HEIGHTS FOR CNTRL PLAINS FROM LATE IN THE WEEK THROUGH EARLY NEXT
WEEK. THUS KEPT TEMPERATURES SLIGHTLY WARMER FRI AND MONDAY BUT
OVERALL LITTLE DEVIANCE FROM GUIDANCE. LEFT FORECAST DRY EVEN
THOUGH 12Z GFS SHOWED A WEAK WAVE AND LIGHT QPF DROPPING OVER RIDGE
THRU NEBR ON FRIDAY AND ECMWF HAD INTERMITTENTLY SPIT OUT PCPN THAT
PD AS WELL. THIS WILL HAVE TO BE MONITORED IN LATER
FORECASTS...PROBABLY IF NOTHING ELSE BUT WAVE POSSIBLY CREATING A
BIT STRONGER WARM ADVECTION AND POSSIBLY WARMER TEMPS ON FRIDAY.
&&
.AVIATION...
18Z TAFS
VFR CONDITIONS WILL PREVAIL THRU THE FCST PD. A WIND SHIFT TO THE
NORTHWEST WL BE MOVING ACROSS TAF SITES THRU 00Z/28.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY/CHERMOK/KERN