FXUS63 KOAX 152114
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
314 PM CST MON NOV 15 2010
.SHORT TERM...TONIGHT THROUGH THURSDAY
NORTHWEST FLOW CONTINUES OVER THE REGION WITH NEXT UPSTREAM WAVE
CURRENTLY OVER CNTRL SD PER LATEST WATER VAPOR IMAGERY. SAID WAVE IS
RATHER FAST MOVING AND FORECAST TO MOVE INTO NERN NEB BY 06Z TONIGHT
AND INTO NERN IA BY 18Z TUE. A FEW SCATTERED SHOWERS ARE SHOWING
UP ACROSS PORTIONS OF CNTRL AND ERN SD AND ACROSS CENTRAL NEB IN
ASSOCIATION WITH THIS WAVE. ISOLATED CONVECTION IS ALSO POPPING UP
ACROSS CNTRL NEB THIS AFTERNOON. NOT EXACTLY SURE HOW MUCH IS REACHING THE
GROUND THIS AFTERNOON DUE TO DRY LOW LEVELS BUT THE ACTIVITY
ACROSS SD SHOULD CONTINUE TO MOVE INTO THE NWRN CWA LATE THIS
AFTERNOON/EARLY THIS EVENING. WL ADD SOME SPRINKLES ACROSS
SOUTHERN HALF OF CWA WHERE WE DO NOT HAVE ANY POPS MENTIONED. PCPN
AMOUNTS LOOK TO REMAIN FAIRLY LIGHT AS MOISTURE REMAINS LIMITED.
DID NOT MENTION -RASN MIX UNTIL AFTER 06Z ACROSS FAR NERN CWA WHEN
FORECAST SOUNDINGS INDICATE A TRANSITION. BY THEN THE SYSTEM
SHOULD BE EXITING THE CWA AND THEREFORE NOT ANTICIPATING ANY
ACCUMULATING SNOW.
TUESDAY CONTINUES TO LOOK DRY AS NEXT UPPER CLIPPER MOVES ACROSS THE
NRN ROCKIES. THERE REMAINS SOME MODEL TIMING AND PLACEMENT ISSUES IN
REGARDS TO THIS NEXT WAVE BUT HAVE GONE CLOSER TO A GFS/ECMWF BLEND
THIS FORECAST. AHEAD OF THE SYSTEM...STRONG WAA AND ISENTROPIC
LIFT WL BE THE ONSET OF PCPN IN OUR WESTERN COUNTIES TUESDAY
EVENING. MOISTURE RETURN WL BE THE MAIN FACTOR ON HOW FAR EAST THE
PCPN CAN MAKE IT TUE EVE.
THE MID WEEK CLIPPER IS FORECAST TO CLOSE OFF ON TOP OF THE CWA BY
12Z WED PER 12Z GFS. THE NEW 12Z ECMWF CLOSES THE LOW OFF OVER NORTH
CENTRAL KANSAS BY 12Z WED AND CONTINUES ON A SERLY TRACK. HAVE NOT
YET DISCOUNTED EITHER TRACK AND THEREFORE HAVE GONE WITH A BLEND OF
THE TWO. IN ANY CASE...SFC COLD FRONT SHOULD MOVE ACROSS THE CWA EARLY
WED MORNING GIVING US NON-DIURNAL TEMPS FOR THE DAY. PCPN SHOULD
BEGIN TO CHANGE OVER/MIX WITH SNOW AFTER 06Z WED IN THE FAR NORTH
WITH A QUICK TRANSITION OVER TO ALL SNOW DURING EARLY WED MORNING.
HIGHEST ACCUMULATIONS SHOULD REMAIN OVER NERN NEB IF GFS IS
ACCURATE. IF MODELS COME INTO BETTER AGREEMENT WITH THE 12Z ECMWF...WE
WL BE SHIFTING OUR HEAVIEST ACCUMULATIONS TO THE SOUTHWEST. ONLY
EXPECTING LIGHT ACCUMULATIONS ALONG THE I-80 CORRIDOR IF ANY AT
ALL. CRITICAL TEMPERATURES WILL BE MARGINAL FOR RAIN AND/OR SNOW.
SYSTEM SHOULD BE CLEAR OF THE AREA BY 00Z THURSDAY WITH 850MB WAA
RETURNING ON THURSDAY.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY.
EXTENDED FORECAST STILL SHOWS A DEVELOPING LARGE-SCALE WEST COAST
TROUGH WITH WSW UPPER FLOW AFFECTING CENTRAL PLAINS INCLUDING OAX
CWA THROUGH NEXT WEEKEND AND BEYOND. STRENGTH AND LATITUDE OF ANY
EJECTING SHORTWV TROUGHS WILL GREATLY INFLUENCE TEMPERATURES AS
QUITE COLD AIR WILL BE SPILLING INTO THE NORTHERN PLAINS WITH UPPER
FLOW PROVIDING FAVORABLE CONDITIONS FOR VERY WARM TEMPERATURES NOT
TOO FAR TO OUR SOUTH. THIS FORECAST WAS BASED MORE ON A COMPROMISE
BETWEEN PREVIOUS FORECAST AND 00Z ECMWF...THE LATTER WAS FAVORED BY
HPC. THIS WOULD KEEP TEMPERATURES ABOVE 12Z MEX FRI AND SAT AS A
WEAK FRONT...MORE OF A MODIFIED CANADIAN ONE...SLIPS INTO FCST AREA
FRIDAY AND WASHES OUT/REDEVELOPS NEAR SD BORDER SAT AS STRONGER WAVE
EJECTS ACROSS NRN ROCKIES. THEN SEVERAL REINFORCING PUSHES OF
COLDER AIR/FRONTS IN SUNDAY/MONDAY PERIOD CROSS FORECAST AREA WITH A
COOLING TREND AND BELOW MEX TEMPERATURES...SPCLY BY MONDAY. WOULD
SUSPECT EVENTUALLY WITH SWRLY UPPR FLOW THAT AN EJECTING WAVE WILL
BRING POST-FRONTAL PCPN TO FCST AREA...AND DECIDED ON THE SUN
NGT/MON PD TO INCLUDE WHEN THE SECOND AND STRONGER PUSH OF COLD AIR
CROSSES FORECAST AREA. HOWEVER...CONFIDENCE IN TEMPERATURE FORECAST
EVEN LOWER THAN PCPN FORECAST WITH TEMPERATURES POSSIBLY ENDING UP
SEVERAL CATEGORIES OFF EITHER DIRECTION DEPENDING ON TIMING/STRENGTH
OF ANY OF THE FRONTS.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
GENERALLY EXPECTED VFR CONDS THRU THE NEXT 24 HR. UPPR LVL PV
ANOMALY OVR SODAK THIS AFTN WL ROTATED THRU ERN NEB THIS EVNG ALNG
WITH AN INCREASE IN CLDS. CLD DECKS SHLD GENERALLY BE 4 TO 6 K
FT...BUT MAY DIP INTO MVFR RANGE IF A SHOWER IMPACTS A TERMINAL.
THIS IS MOST LIKELY AT OMA/OFK...BUT WL LEAVE FORECAST DRY ATTM DUE
TO VERY ISO NATURE OF THE ACTIVITY. CLDS WL CLEAR FM OFK TO LNK BY
MRNG WITH SCT MID LVL CLDS INTO THE DAY ON TUE. LIGHT AND VARIABLE
WNDS THIS AFTN SHLD GIVE WAY TO NWRLY LO LVL FLOW AFTER MIDNIGHT AT
ALL LOCATIONS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
KERN/CHERMOK/BOUSTEAD