FXUS63 KOAX 250755
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
255 AM CDT MON OCT 25 2010
.DISCUSSION...
COLD FRONT WILL SWEEP THROUGH THE REGION LATE THIS AFTERNOON AND
EVENING AND BRING US A DECENT SHOT FOR SOME RAINFALL ALONG AND
BEHIND THE FRONT. BEFORE THE RAIN ARRIVES THOUGH...CIRRUS HAS BEEN
STREAMING ACROSS THE REGION AND BEGINNING TO THICKEN ACROSS
NORTHEAST NEBRASKA...AS GRADIENT WINDS ALSO BEGIN TO INCREASE.
HOWEVER...AREAS OF FOG HAD DEVELOPED PRIOR TO THE ARRIVAL OF THE
CLOUDS...WITH PATCHY DENSE FOG NOTED ESPECIALLY ACROSS WESTERN
IOWA AND A COUPLE OF SPOTS IN EASTERN NEBRASKA. WILL HAVE TO SEE
HOW THIS EVOLVES OVER THE NEXT HOUR OR TWO...BUT INCREASING SURFACE
WINDS THROUGH DAYBREAK ALONG WITH INCREASING CLOUDS OVERHEAD
SHOULD BEGIN TO SCATTER THIS OUT. MODELS ALL STILL SUGGEST BEST
INSTABILITY WILL BE EAST OF THE CWFA FORECAST BOUNDARY ACROSS
CENTRAL IOWA AND MISSOURI THIS AFTERNOON AND EVENING THUS STILL
HAVE NOT ADDED MENTION OF THUNDER TO OUR FORECAST GRIDS. TEMPS
AHEAD OF THE FRONT SHOULD REACH THE LOWER/MID 70S...ALTHOUGH THAT
COULD BE TRICKY TOO WITH THICKENING CIRRUS OVERHEAD.
RAIN DOES MOVE THROUGH THE REGION OVERNIGHT AND SHOULD END FROM
WEST TO EAST BY DAYBREAK TUESDAY. SUBSTANTIAL CYCLOGENESIS TAKES
PLACE OVERNIGHT WITH RAPID DEEPENING OF THE SURFACE LOW ACROSS THE
MID MISSISSIPPI RIVER VALLEY ON TUESDAY. ON THE BACK SIDE OF
THIS...WEST NORTHWEST GRADIENT WINDS WILL BE INCREASING THROUGH
THE DAY. H85 WINDS ARE PROGGED TO BE AROUND 45KTS...THUS NORTHERN
HALF OF THE CWFA DOES HAVE A VERY HIGH PROBABILITY OF MEETING WIND
ADVISORY CRITERIA OF SUSTAINED WINDS OF 30 MPH OR HIGHER. GUST
POTENTIAL EASILY COULD REACH THE MID 40S TUESDAY AFTERNOON...AND
FEEL WINDS SHOULD BE JUST SHY OF HIGH WIND WARNING CRITERIA...THUS
HAVE NO PLANS TO ISSUE A HIGH WIND WATCH AT THIS TIME...ALTHOUGH
A WIND ADVISORY WILL EVENTUALLY BE NEEDED.
THE WINDS DO DIMINISH BY SUNSET TUESDAY EVENING...BUT SHOULD
INCREASE AGAIN ON WEDNESDAY TO NEAR ADVISORY LEVEL ONCE MORE AS
THE SURFACE LOW CONTINUES TO DEEPEN...BUT MOVES INTO SOUTHERN
CANADA. DUE TO AN EVEN TIGHTER PRESSURE GRADIENT...AGAIN THE
NORTHERN HALF OF THE CWFA DOES HAVE POTENTIAL TO REACH 30 MPH
SUSTAINED WINDS...WITH GUSTS AGAIN APPROACHING THE MID 40S...
DESPITE THE FACT THE SURFACE LOW IS FURTHER AWAY. THIS DOES ALLOW
SOME COOLER TEMPERATURES TO FILTER DOWN THROUGH THE NORTHERN
PLAINS AS WELL...WITH BOTH GFS/ECMWF KEEPING PRECIPITATION JUST
NORTH OF THE REGION ACROSS SOUTH DAKOTA...MINNESOTA AND EXTREME
NORTHWEST IOWA.
BEYOND THEN...AN UPPER RIDGE BUILDS ACROSS THE REGION WITH TEMPERATURES
WARMING ONCE AGAIN THROUGH AT LEAST THE FIRST HALF OF THE WEEKEND.
LATEST GFS/ECMWF ARE IN DECENT AGREEMENT WITH A WEAK WEATHER
DISTURBANCE MOVING OUT OF THE ROCKIES BY SUNDAY THOUGH...WHICH THE
DAY SHIFT WILL HAVE TO TAKE A GOOD LOOK AT.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
MAIN ISSUES THIS FCST CYCLE INCLUDE STRONG WINDS AND DETERIORATING
CONDITIONS WITH ANTICIPATED COLD FROPA. STRENGTHENING DUEL SFC LOWS
...ONE OVER THE DAKOTAS AND OTHER OVER KS...WILL RESULT IN
TIGHTENING PRESS GRADIENT OVER THE PLAINS AHEAD OF APPROACHING COLD
FRONT. SLY WIND GUSTS 25KT-30KT LIKELY AT ALL TERMINALS AROUND 17Z
THIS AFTN. EXPECT FROPA/WIND SHIFT TO NW AROUND 22Z AT KOFK AND
KLNK...THEN 26/00Z AT KOMA. SFC WIND SPEED WITH INITIAL SHIFT TO NW
SHOULD BE AROUND 10KT THEN QUICKLY STRENGTHEN WITH GUSTS 20KT-30KT
THE REST OF THE FCST PD. DECREASING FLT CAT COND EXPECTED TO
ACCOMPANY FROPA AT ALL TERMINALS...VFR TO MVFR WITH SHRA.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
DISCUSSION...DEWALD
AVIATION...DEE