FXUS63 KOAX 012141
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
341 PM CST TUE FEB 1 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY.
ONGOING SNOW AND WIND WILL BE THE PRIMARY CONCERN...WITH COLD
TEMPERATURES AND WIND CHILLS LATER TONIGHT A CLOSE SECOND.
POTENT STORM SYSTEM CONTINUED TO LIFT NORTHEAST FROM THE SOUTHERN
PLAINS INTO THE MIDWEST WITH MAIN SURFACE LOW RIDING UP THE
MISSISSIPPI SOUTH OF ST. LOUIS. WELL-DEFINED DRY SLOT WAS NOTED ON
WATER VAPOR IMAGERY POKING INTO CENTRAL MISSOURI...WITH EXTENSIVE
COMMA HEAD CLOUD FORMATION EXTENDING EAST TO WEST FROM CHICAGO
INTO CENTRAL NEBRASKA. SNOW HAD INCREASED IN INTENSITY THROUGH THE
MORNING IN NORTHEAST KANSAS AND NORTHWEST MISSOURI...AND SPREAD
NORTHWEST INTO EASTERN NEBRASKA AND SOUTHWEST IOWA LATE MORNING
AND EARLY AFTERNOON. AT 3 PM...THAT ENHANCED SNOW INTENSITY HAD
SPREAD TO AND NORTH OF INTERSTATE 80...GENERALLY AS FAR NORTH AS A
DUNLAP TO MISSOURI VALLEY...OMAHA/VALLEY...WAHOO AND SEWARD LINE.
WIND SPEEDS ALSO INCREASED THROUGH THE DAY AS PRESSURE GRADIENT
INTENSIFIED BETWEEN 1000MB LOW IN SOUTHEAST MISSOURI AND 1054MB
HIGH IN EASTERN MONTANA. NORTH WINDS WERE AVERAGING 15 TO 25 MPH
WITH GUSTS OVER 30 MPH ACROSS EASTERN NEBRASKA AND SOUTHWEST IOWA.
THE COMBINATION OF FALLING AND BLOWING SNOW WAS CAUSING NEAR
BLIZZARD CONDITIONS IN WESTERN IOWA AND SOUTHEAST NEBRASKA AND
MANY REPORTING STATIONS INDICATED HALF MILE OR LESS VISIBILITIES
THROUGH THE AFTERNOON. FARTHER TO THE NORTHWEST...LIGHTER FALLING
SNOW WAS NOTED AND VISIBILITIES WERE GENERALLY NEAR OR ABOVE A
MILE. CONSIDERED BLIZZARD WARNING FOR THIS EVENING WHERE MORE
INTENSE SNOW WAS FALLING...BUT OPTED TO STICK WITH CURRENT WINTER
STORM WARNING AND HIGHLIGHT THE NEAR BLIZZARD CONDITIONS WITH BRIEF
WHITE-OUT CONDITIONS FOR TRAVELLERS THIS EVENING.
CURRENT SPEED/TRACK OF SYSTEM SUGGESTS SNOW WILL LIKELY LINGER A
BIT LONGER IN FAR EASTERN NEBRASKA AND WESTERN IOWA THAN PREVIOUS
MODEL FORECASTS INDICATED. THIS IS OFTEN THE CASE WITH LARGE
SYSTEMS IN DEFORMATION ZONE/COMMA HEAD REGIONS. AND LATEST SHORT
RANGE MODEL FORECASTS ARE BEGINNING TO HINT AT THIS. THUS HAVE
EXTENDED OUR WINTER STORM WARNINGS A TAD LONGER IN EASTERN
NEBRASKA AND WESTERN IOWA...HOLDING ON UNTIL MIDIGHT AND 3 AM
RESPECTIVELY. ADDITIONAL SNOWFALL BETWEEN 3 PM AND 3 AM COULD
REACH 3 TO 5 INCHES IN SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA...WITH 1 TO 3 INCH ADDITIONAL SNOWS ALONG THE INTERSTATE 80
CORRIDOR. THIS WOULD BRING STORM TOTAL SNOWS INTO THE RANGE OF 4
TO 7 INCHES ALONG INTERSTATE 80 TO ABOUT 6 TO 9 IN FAR SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA.
AFTER THE SNOW ENDS...BLOWING AND DRIFTING SNOW WILL STILL BE AN
ISSUE. HOWEVER THE MAIN WEATHER STORY WILL LIKELY BE THE DANGEROUS
WIND CHILLS. AIR TEMPERATURES ARE FORECAST TO DROP WELL BELOW ZERO
IN NORTHEAST NEBRASKA...WITH ZERO TO 5 BELOW MORE COMMON IN
SOUTHWEST IOWA LATE TONIGHT. THIS COMBINED WITH WIND SPEEDS OF 15
TO 25 MPH WILL PUSH WIND CHILL IDICES CLOSE TO 35 BELOW IN
NORTHEAST NEBRASKA AND AROUND 25 BELOW ACROSS THE REST OF EASTERN
NEBRASKA AND WESTERN IOWA. THUS WILL CONTINUE OUR WIND CHILL
WARNINGS FOR NORTHEAST NEBRASKA AND WIND CHILL ADVISORIES FOR THE
REST OF THE AREA.
TEMPERERATURES WILL BE HARD PRESSED TO RISE MUCH ON WEDNESDAY
DESPITE DECREASING CLOUDS. HAVE MOST HIGHS IN THE SINGLE DIGITS
ABOVE ZERO. ANOTHER COLD NIGHT WEDNESDAY NIGHT WITH WINDS AND
CLOUDS DECREASING OVER FRESH SNOW COVER. WINDS WILL START TO TURN
TO THE SOUTHWEST OVERNIGHT...SO PERHAPS NORTHEAST NEBRASKA MAY
HOLD CLOSE TO ZERO...BUT EXPECTED SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA TO APPROACH 10 BELOW WHERE WINDS WILL BE SLOW TO INCREASE.
THAT SOUTHWEST FLOW SHOULD WARM TEMPS WELL INTO THE TEENS ON
THURSDAY WITH PLENTY OF SUNSHINE. THEN EVEN WARMER CONDITIONS ARE
FORECAST FRIDAY AS NORTHWEST WINDS KICK UP.
DERGAN
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
LATEST MEDIUM RANGE DETERMINISTIC MODELS IN PRETTY GOOD AGREEMENT
THAT MEAN LARGE SCALE PATTERN WILL PERSIST WITH AN UPPER RIDGE OVER
THE WEST COAST WITH A DEEP TROF COVERING THE EASTERN STATES. AS ONE
WOULD EXPECT...THE GREAT PLAINS WILL SEE ANOTHER INTRUSION OF
BITTERLY COLD AIR DURING THE FORECAST PERIOD. MORE DIFFICULT THOUGH
IS TRYING TO TIME THE AIRMASS AS WELL AS GUESS WHICH PIECE OF ENERGY
RIDING DOWN THE FRONT SIDE OF THE WESTERN RIDGE MAY INDUCE SNOW.
REGARDING TEMPS...LATEST GFS IS MUCH FASTER THRUSTING THE BULK OF
THE COLD AIR ADVECTION INTO THE CENTRAL PLAINS...WHILE THE ECM/CMC
LAG ABOUT 12 HRS BEHIND. NEVERTHELESS....CONFIDENCE IS RATHER HIGH
THAT THE CWA WILL EVENTUALLY SEE A SIGNIFICANT TEMP DROP. DO NOT
HAVE A GOOD FEEL EITHER WAY WHETHER FASTER GFS OR SLOWER ECM/CMC
SOLUTION WILL BE REALIZED. THEREFORE WILL USE COMPROMISE AND PUSH
THE ARCTIC AIR INTO THE CWA EARLY MONDAY. AS FOR POSSIBLE
SNOW...THINK THAT SMALL CHANCES COVERING FRIDAY NIGHT/SUNDAY
NIGHT/MONDAY PERIODS REASONABLE GIVEN IMPULSES WILL BE INTERACTING
WITH SURFACE BOUNDARIES PASSING THROUGH.
DEE
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
PERIODS OF IFR CEILINGS AND VISIBILITIES LIKELY THROUGH 02/03Z AS
DEEP LOW PRESSURE OVER NORTHEAST ARKANSAS MOVES TOWARD SOUTHERN
ILLINOIS AND SPREADS MODERATE TO LIGHT SNOW ACROSS THE AREA. THE
COMBINATION OF SNOW AND WINDS WILL RESULT IN BLOWING SNOW THROUGH
MUCH OF TONIGHT WITH MVFR CONDITIONS AT TIMES. WINDS SHOULD BEGIN TO
SUBSIDE AFTER 12Z WITH LOW LEVELS DRYING OUT VFR CONDITIONS EXPECTED
AT ALL THREE SITES.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR NEZ045-
050>053-065>068-078-088>093.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST WEDNESDAY
FOR NEZ045-050>053-065>068-078-088>093.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ015-
033-034-043-044.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON CST WEDNESDAY
FOR NEZ015-033-034-043-044.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR NEZ011-
012-016>018-030>032-042.
WIND CHILL WARNING FROM 9 PM THIS EVENING TO NOON CST WEDNESDAY
FOR NEZ011-012-016>018-030>032-042.
IA...WINTER STORM WARNING UNTIL 3 AM CST WEDNESDAY FOR IAZ055-056-069-
079-080-090-091.
WIND CHILL ADVISORY FROM 3 AM TO NOON CST WEDNESDAY FOR IAZ055-
056-069-079-080-090-091.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ043.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO NOON CST WEDNESDAY
FOR IAZ043.
&&
$$