FXUS63 KOAX 122045
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
345 PM CDT TUE APR 12 2011
.SHORT TERM...TONIGHT.
GUSTY SOUTHWEST WINDS HAVE MIXED DRIER AIR FROM JUST OFF THE SURFACE
DOWNWARD THIS AFTERNOON...PUSHING RELATIVE HUMIDITIES TO BELOW 20
PERCENT IN NORTHEAST NEBRASKA. THE LOW HUMIDITY AND GUSTY WINDS
COMBINED WITH DRY FUELS HAS PROMPTED THE ISSUANCE OF A RED FLAG
WARNING FOR MOST OF NORTHEAST NEBRASKA THROUGH THE AFTERNOON FOR
DANGEROUS FIRE WEATHER CONDITIONS. DECREASING WINDS AND SOME DEW
POINT/RELATIVE HUMIDITY RECOVERY LATE THIS AFTERNOON WILL LIMIT FIRE
POTENTIAL THEN.
OTHERWISE CLEAR SKIES THIS AFTERNOON WILL BE REPLACED BY MID AND
HIGH LEVEL CLOUDS MOVING IN FROM THE WEST. A COLD FRONT MOVING
THROUGH CENTRAL SOUTH DAKOTA AT MID AFTERNOON IS FORECAST TO ENTER
NORTHEAST NEBRASKA AFTER MIDNIGHT...APPROACHING A COLUMBUS TO
TEKAMAH LINE BY SUNRISE WEDNESDAY. LIGHT NORTHEAST WINDS WILL FOLLOW
THE FRONT...BUT THE INCREASE IN CLOUDS SHOULD HOLD TEMPERATURES IN
THE MIDDLE 40S EVEN BEHIND THE FRONT. FOR SOUTHEAST NEBRASKA AND
SOUTHWEST IOWA...WOULD EXPECT A QUICK FALL TO TEMPS THIS
EVENING...THEN STEADY AFTER MIDNIGHT AS LIGHT SOUTH WINDS CONTINUE
UNDER INCREASING CLOUD COVER. HAVE LOW THERE IN THE UPPER 40S TO
LOWER 50S.
.LONG TERM...WEDNESDAY THROUGH TUESDAY
WEDNESDAY THROUGH FRIDAY...WE WILL HAVE SEVERAL FORECAST CONCERNS
RELATED TO A MID TROPOSPHERIC TROUGH OFF THE WEST COAST THAT MOVES
INTO THE CENTRAL PLAINS AND CLOSES OFF OVER KANSAS THURSDAY AND
REMAINS OVER KANSAS/MISSOURI INTO FRIDAY.
INITIALLY...A SHORTWAVE TROUGH OVER SOUTHERN CANADA WILL DRAG A
COLD FRONT THRU THE FORECAST AREA WEDNESDAY. CONDITIONS LOOK A BIT
DRY SOUTH OF FRONT AND BEFORE THE CLOUDS MOVE IN...TEMPERATURES
SHOULD HAVE A CHANCE TO WARM INTO THE 60S AND 70S EXCEPT IN THE
NORTH WHERE READINGS SHOULD HOLD IN THE 50S. THE BEST CHANCE FOR
RAIN BY LUNCH TIME SHOULD BE IN THE NORTH BEHIND THE SFC
FRONT...HOWEVER OTHER ISOLATED SHOWERS AND THUNDERSTORMS MAY
DEVELOP OVER THE REST OF THE FORECAST AREA AS LIFTED INDICES
BECOME NEGATIVE DURING THE AFTERNOON AND COOLING ALOFT STEEPENS
THE LAPSE RATES. STRONGER SHORTWAVE TROUGH ENERGY WILL MOVE INTO
THE PLAINS WEDNESDAY NIGHT AND THURSDAY. PRECIPITATION CHANCES
CONTINUE DURING THE PERIOD WITH PRECIPITATION BECOMING WIDESPREAD
THURSDAY AFTERNOON AND THURSDAY NIGHT. THE LOW LEVEL JET INCREASES
TO 40+KT OVER KS AND THIS DRAWS 10+ DEG C H85 DEWPOINTS NORTHWARD
WITH STRONG LIFT OVER THE FORECAST AREA. PRECIPITABLE WATER VALUES
INCREASE TO OVER 1.25 INCHES AND THIS IS OVER 200% OF NORMAL. DO
HAVE SOME 1 TO 1.5 INCH RAINFALL AMOUNTS THROUGH THURSDAY NIGHT. THE
GFS/ECMWF ARE SIMILAR IN THE TRACK OF THE MID LEVEL LOW...HOWEVER
THE NAM IS A BIT FARTHER NORTH. FOR THIS FORECAST TRENDED MORE
WITH THE ECMWF/GFS TRACK.
LATE THURSDAY NIGHT AND FRIDAY THE STORM
SYSTEM PULLS IN COLDER AIR WITH A RAIN SNOW MIX AND PERIODS OF ALL
SNOW POSSIBLE FOR THE CWA. THE BEST LOCATIONS FOR ACCUMULATIONS
APPEAR TO BE IN THE WESTERN CWA. SOIL TEMPERATURES ARE IN THE 40S
AND 50S...SO THIS WILL HINDER SNOW ACCUMULATION OF ROADS. THE WWD
(HYDROMETEOROLOGICAL PREDICTION CENTER WINTER WEATHER DESK)
APPEARS TO BE USING GFS MODEL QPF AND A 10:1 RATIO WITH OVER A
FOOT OF SNOW IN OUR WESTERN CWA. STRONG NORTHWEST WINDS WILL ALSO
OCCUR ON THE BACKSIDE OF THE STORM SYSTEM.
IT IS IMPORTANT TO KEEP IN MIND THAT THE STORM SYSTEM IS YET TO
COME ONTO THE WEST COAST WHERE SAMPLING WILL BE BETTER...BUT AT
THIS TIME...THE DETERMINISTIC ARE IN GOOD AGREEMENT WITH THE STORM
SYSTEM AND THAT IS WILL BE A SIGNIFICANT WEATHER PRODUCER.
FRIDAY NIGHT THE STORM SYSTEM WILL BE EXITING THE AREA WITH THE
CLOSED MID TROPOSPHERIC LOW IN THE VICINTY OF SOUTHEAST IOWA OR WEST
CENTRAL ILLINOIS. THE FORECAST AREA WILL BE ON THE BACKSIDE WITH
GUSTY NORTHWEST WINDS AND TEMPERATURES IN THE 20S TO AROUND FREEZING
SOUTHEAST. AM COUNTING ON THE WINDS AND CLOUDS HOLDING TEMPS UP.
RECORDS FOR THE 16TH ARE 14 AT OFK AND 21 AT OMA/LNK.
THERE IS A BREAK IN PRECIPITATION SATURDAY AND TEMPERATURES SHOULD
REBOUND INTO THE 40S AND 50S. TEMPERATURES IN THE NORTH MAY BE HELD
DOWN WITH MORE CLOUDS. SATURDAY NIGHT INTO SUNDAY THERE IS WAIR AIR
RETURNING AHEAD OF A FRONTAL PASSAGE AND AT THIS TIME WE HAVE SOME
SHOWERS POSSIBLE. COULD EVENING LOWS WITH RISING OVERNIGHT
TEMPERATURES. THE FRONT DOES NOT SEEM TO HAVE A LOT OF MOISTURE WITH
IS...BUT CONTINUE POPS INTO SUNDAY. THERE ARE LOCATION DIFFERENCES
AND STRENGTH DIFFERENCES WITH THE FRONT SUNDAY. FOR NOW HAVE HIGHS
IN THE 40S NORTH AND 50S SOUTH. STILL TIMING DIFFERENCES WITH THE
POTENTIAL FOR PRECIPITATION WITH LIFT OVER THE FRONT OVER THE COUNTY
FORECAST AREA...OR WHETHER THE FRONT WILL BE WELL TO THE SOUTH.
KEPT TEMPERATURES BELOW NORMAL FOR MONDAY AND TUESDAY WITH THE
CHANCE FOR SHOWERS.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH NOON WEDNESDAY. GUSTY
SOUTHWEST WINDS UP TO 25KTS WILL AFFECT THE KOFK AREA THROUGH 00Z.
OTHERWISE EXPECT LIGHT SOUTH WINDS BECOMING SOUTHEAST THEN EAST
AFTER 12Z AS A COLD FRONT APPROACHES FROM THE NORTHWEST. THAT FRONT
WILL MOVE TO KOFK BY 18Z. MID LEVEL CIGS NEAR FL080-100 SHOULD
INVADE EASTERN NEBRASKA BETWEEN 12Z AND 18Z. A GRADUAL LOWERING OF
CIGS WILL OCCUR AFTER 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR NEZ011-012-
016>018-030>032-042.
IA...NONE.
&&
$$
DERGAN/ZAPOTOCNY/DERGAN