FXUS63 KOAX 142006
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
306 PM CDT THU APR 14 2011
.SHORT TERM...TONIGHT.
DEEP UPPER TROUGH COMING INTO THE SOUTHERN PLAINS IS FORECAST TO
CLOSE OFF AND INTENSIFY OVER KANSAS TONIGHT WITH WIDESPREAD RAIN
DEVELOPING ACROSS EASTERN NEBRASKA AND SOUTHWEST IOWA. ISOLATED
THUNDERSTORMS ALSO POSSIBLE THROUGH THE EVENING IN SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA...MAINLY BEFORE MIDNIGHT.
FOBERT
.LONG TERM...FRIDAY THROUGH THURSDAY.
CONTINUING RAIN THROUGH FRIDAY NIGHT AND THE CHANCE FOR A MIX WITH
OR CHANGE TO SNOW ARE THE PRIMARY FORECAST CONCERNS. THEN AN
UNSETTLED WEATHER PATTERN NEXT WEEK WILL BRING OCCASIONAL SMALL RAIN
CHANCES.
RAIN SHOULD BE ONGOING FRIDAY MORNING AS LOW PRESSURE SYSTEM MOVES
EAST THROUGH EASTERN KANSAS. STRONG THETA-E ADVECTION FROM 850-700MB
IN THE MORNING WILL GRADUALLY SHIFT EAST IN THE AFTERNOON...FOCUSING
BRUNT OF HEAVIEST PRECIP ACROSS IOWA AND EAST. HOWEVER CONVEYOR BELT
WRAPPING AROUND LOW WILL CONTINUE TO BRING RAIN TO MUCH OF THE CWA
THROUGH FRIDAY AFTERNOON. RAIN AMOUNTS FROM MODEL FORECASTS SUGGEST
OVER AN INCH OF RAIN IS POSSIBLE OVER A LARGE PART OF THE CWA. COLD
AIR SPILLING INTO THE AREA COULD ALSO CHANGE SOME OF THE RAIN OVER
TO SNOW STARTING IN NORTHEAST NEBRASKA BY LATE FRIDAY MORNING.
INVERTED SURFACE-850MB TROUGH POSITION FROM KANSAS LOW NORTH THROUGH
THE CWA WILL SEPARATE RELATIVELY WARM AIR TO THE EAST AND COLDER AIR
TO THE WEST. FORECAST SOUNDINGS SUGGEST NORTHWEST CWA WILL SEE A
CHANGE TO RAIN SNOW MIX BEFORE NOON...WITH THE MIX SPREADING TO A
WAYNE TO COLUMBUS LINE BY LATE IN THE DAY. GIVEN DAYTIME SNOWFALL
AND RELATIVELY WARM SURFACE TEMPERATURES...AM ONLY EXPECTING LIGHT
AMOUNTS IN OUR FAR NORTHWEST BEFORE SUNSET.
THE COLD AIR WILL PUSH FARTHER SOUTHEAST WITH TIME FRIDAY
NIGHT...AND FORECAST SOUNDINGS SUGGEST A CHANGE TO RAIN/SNOW MIX AS
FAR SOUTHEAST AS INTERSTATE 80 AFTER MIDNIGHT. HOWEVER PRECIPITATION
WILL BE MOVING EAST AT THE SAME TIME...SO AMOUNTS WILL BE LIGHT IF
ANY ACCUMULATION OCCURS THERE. FARTHER TO THE NORTHWEST...WILL
LIKELY SEE SOME SNOW ACCUMULATION DURING FRIDAY EVENING AS PRECIP
CHANGES OVER TO ALL SNOW. BUT AGAIN...AMOUNTS OF AN INCH OR LESS
LOOK TO BE ALL WE CAN MUSTER.
TEMPERATURES ON FRIDAY WILL CLIMB TOWARD 50 IN THE EAST...BUT
STRUGGLE TO NUDGE UP A COUPLE OF DEGREES IN THE WEST WHERE NORTHERLY
LOW LEVEL FLOW KICKS IN EARLY. TIGHT PRESSURE GRADIENT WILL KEEP
BRISK WINDS BLOWING...BUT LOOK TO REMAIN BELOW ADVISORY LEVELS.
COULD SEE OCCASIONAL GUSTS TO 40 MPH AS PRECIP HELPS TO MIX DOWN
40KT 850 FLOW.
CLEARING SKIES FROM WEST TO EAST ARE EXPECTED SATURDAY. SATURDAY
MORNING LOWS SHOULD BE HELD NEAR OR ABOVE FREEZING MOST AREAS...BUT
COULD SEE SOME 20S IN THE WEST IF CLOUDS CLEAR BEFORE SUNRISE. HIGHS
SATURDAY SHOULD REBOUND INTO THE 50S WITH SUNSHINE AND MIXING
WESTERLY WIND COMPONENT. A LITTLE WARMER SUNDAY...BUT COULD SEE A
PASSING SHOWER...ESPECIALLY IN THE NORTH AS ANOTHER WEAK MID LEVEL
WAVE TRANSLATES EAST THROUGH THE DAKOTAS.
FOR MONDAY THROUGH THURSDAY TIME FRAME UPPER FLOW WILL FAVOR A
SHALLOW TROUGH OVER MUCH OF THE COUNTRY. BOTH ECMWF AND GFS SHOW
RELATIVELY DEEP SHORTWAVE DRIFTING INTO THE REGION MONDAY NIGHT
THROUGH TUESDAY NIGHT ALONG WITH ASSOCIATED FRONTAL BOUNDARY SAGGING
THROUGH THE CWA. WILL CONTINUE FAIRLY HIGH POPS DURING THIS TIME
WITH COOL TEMPERATURES IN THE 50S.
DERGAN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS WILL START OFF THE PERIOD AT BOTH KLNK AND KOMA WHILE
IFR CONDITIONS WILL LINGER AT KOFK THROUGH 00Z AS CLOSED UPPER LOW
MEANDERS SLOWLY ACROSS THE CENTRAL PLAINS TONIGHT INTO FRIDAY.
CONDITIONS ARE EXPECTED TO BECOME IFR AT ALL THREE SITES AT OR AFTER
12Z AS THE SURFACE LOW MOVES OFF TO THE EAST OF THE AREA AND COLD
ADVECTION FOLLOWS IN ITS WAKE. STRONG EAST WINDS WILL ALSO OCCUR
IN ADVANCE OF THE LOW ACROSS EASTERN NEBRASKA INTO TONIGHT AND
PROVIDE STRONG CROSS WIND COMPONENT TO AREA RUNWAYS. SHOWERS WILL
BECOME WIDESPREAD ACROSS THE AREA TONIGHT INTO FRIDAY WITH LOWERING
CEILINGS.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 1 AM CDT FRIDAY FOR NEZ030>034-042>045-
050>053-065>068-078-088>093.
IA...WIND ADVISORY UNTIL 1 AM CDT FRIDAY FOR IAZ055-056-069-079-080-
090-091.
&&
$$