Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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742
FXUS63 KOAX 091118
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
518 AM CST TUE FEB 9 2016

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 310 AM CST TUE FEB 9 2016

PRIMARY FORECAST CONCERN IS PRECIPITATION CHANCES TONIGHT INTO
WEDNESDAY.

A DEEP-LAYER CYCLONE CENTERED OVER THE UPPER GREAT LAKES EARLY THIS
MORNING WILL DE-AMPLIFY AS IT GRADUALLY SHIFTS EWD TO OFF THE
ATLANTIC SEABOARD BY ABOUT THURSDAY.  DURING THIS TIME FRAME...AN
UPSTREAM RIDGE WILL REMAIN QUASI-STATIONARY OVER WRN NORTH
AMERICA...WITH THE PREVAILING MID-LEVEL FLOW FROM THE ROCKIES
THROUGH MS VALLEY BECOMING MORE NWLY. IN THE NEAR-TERM
(TODAY)...WINDS HAVE REMAINED GUSTY EARLY THIS MORNING WITH
SUSTAINED SPEEDS OF 15-20 MPH WITH GUSTS TO 25-30 MPH. WHILE NOT
NEARLY AS WINDY AS SUNDAY AND MONDAY...WE WILL LIKELY SEE GUSTY
WINDS CONTINUING THROUGH TODAY...ESPECIALLY ALONG AND EAST OF THE
MISSOURI RIVER. INCREASING CLOUDS FROM THE WEST AND LITTLE CHANGE
TO THE CHARACTER OF THE LOW-LEVEL THERMODYNAMIC ENVIRONMENT WILL
RESULT IN HIGHS MAINLY IN THE 20S.

00Z MODEL GUIDANCE IS IN REASONABLE AGREEMENT IN SUGGESTING THAT
A LOW-AMPLITUDE CLIPPER-TYPE SYSTEM WILL TRAVERSE THE CANADIAN
PRAIRIE PROVINCES TONIGHT BEFORE DIVING SEWD INTO THE UPPER MS
VALLEY AND EVENTUALLY OH VALLEY WEDNESDAY INTO WEDNESDAY NIGHT.
THIS UPPER-AIR SYSTEM WILL BE ATTENDED BY A MIGRATORY SURFACE
CYCLONE AND A CHINOOK-TYPE WARM FRONT WHICH IS FORECAST TO SHIFT
EWD THROUGH THE NRN AND CNTRL PLAINS TONIGHT INTO WEDNESDAY.
THEREAFTER...A TRAILING COLD FRONT WILL PUSH SWD THROUGH THE MID-
MO VALLEY WEDNESDAY NIGHT.

THE RESPONSE TO STRENGTHENING LOW TO MID-TROPOSPHERIC FRONTOGENESIS
WILL FOSTER A N-S-ORIENTED BAND OF PRECIPITATION OVER THE DAKOTAS
TODAY WHICH WILL SUBSEQUENTLY SPREAD SSEWD THROUGH THE MID-MO
VALLEY TONIGHT INTO WEDNESDAY. FORECAST SOUNDINGS SUGGEST THAT
SNOW WILL BE THE PREDOMINANT P-TYPE...THOUGH A WARM NOSE CENTERED
AROUND 850 MB MAY ALLOW SOME SLEET TO MIX IN TOWARD THE END OF THE
EVENT. THE SYSTEM WILL BE RELATIVELY FAST MOVING WITH THE HIGHEST
SNOW ACCUMULATIONS OF AROUND AN INCH MOST LIKELY BEING OVER OUR
WRN IOWA COUNTIES. SKIES WILL BEGIN TO CLEAR FROM THE WEST BY
AFTERNOON...POTENTIALLY RESULTING IN HIGHS RANGING FROM LOWER 40S
SW TO LOWER 20S OVER OUR W-CNTRL IA COUNTIES.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 310 AM CST TUE FEB 9 2016

FRIDAY INTO SATURDAY...MEDIUM-RANGE MODELS ARE IN GENERAL AGREEMENT
THAT A SERIES OF MID TO UPPER-LEVEL SPEED MAXIMA TRANSLATING FROM
CNTRL CANADA INTO THE OH VALLEY WILL CONTRIBUTE TO THE RE-
INTENSIFICATION OF THE LARGE-SCALE TROUGH PRESENT OVER ERN NORTH
AMERICA. THESE DATA SUGGEST THAT WE WILL BE ON THE WRN FRINGE OF
A SURGE OF COLD CONTINENTAL AIR PLUNGING EQUATORWARD...THE IMPACTS
OF WHICH WILL BE LIKELY FELT ON SATURDAY WITH HIGHS IN THE TEENS
AND 20S.

A FEATURE THAT WE WILL BE WATCHING FOR THIS UPCOMING WEEKEND IS A
SHORT-WAVE TROUGH WHICH IS FORECAST TO MOVE ONTO THE PACIFIC NW
COAST FRIDAY NIGHT OR SATURDAY. THIS SYSTEM WILL THEN AMPLIFY AS IT
PROGRESSES THROUGH THE NRN INTER-MOUNTAIN REGION SATURDAY BEFORE
REACHING THE GREAT PLAINS SUNDAY. THE ECMWF AND CANADIAN MODELS ARE
MORE PROGRESSIVE WITH THIS SHORT-WAVE TROUGH THAN THE DETERMINISTIC
GFS AND GEFS MEAN. HOWEVER...IT IS WORTH NOTING THAT THE LATTER
TWO HAVE TRENDED CLOSER TO THE ECMWF SOLUTION OVER THE PAST 24
HOURS. THE UPSHOT IS THAT WE SHOULD AN INCREASE IN PRECIPITATION
CHANCES LATER THIS WEEKEND.

&&

.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 517 AM CST TUE FEB 9 2016

VFR CONDITIONS THROUGH MOST OF THE PERIOD. NORTHWEST WINDS CONTINUE
TODAY AT 15 TO 25 KNOTS. SHOULD START TO DIMINISH TO 12 KNOTS OR
LESS BY 19-22Z...THEN BECOMING LIGHT AND VARIABLE. MVFR CONDITIONS
COULD RETURN AT KOFK/KLNK BY 08-10Z.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...MEAD
LONG TERM...MEAD
AVIATION...DEWALD



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