FXUS63 KOAX 070400
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1000 PM CST SUN DEC 6 2009
.UPDATE...
UPDATED HEADLINES TO REMOVE PARTS OF NORTHEAST NEBRASKA FROM THE
ADVISORY. REST OF HEADLINES UNCHANGED.
&&
.DISCUSSION...
SNOW SHOULD END AFTER MIDNIGHT WITH ONLY LIGHT ACCUMULATIONS THE
REST OF THE EVENING INTO EARLY MORNING.
NEXT SYSTEM STILL ON TRACK FOR POTENTIAL SNOW FOR PARTS OF THE AREA
MONDAY NIGHT. HEAVIEST LIKELY TUESDAY INTO TUESDAY EVENING. WINDS
MOST LIKELY WILL NOT GET STRONG ENOUGH FOR CONSIDERABLE BLOWING AND
DRIFTING WITH LOW VISIBILITIES UNTIL LATE TUESDAY AFTERNOON OR IN
THE EVENING.
&&
.AVIATION...
&&
.PREV DISCUSSION... /ISSUED 343 PM CST SUN DEC 6 2009/
SHORT TERM...TONIGHT THROUGH WEDNESDAY.
SERIES OF SHORTWAVE TROFS MOVING ACROSS THE CENTRAL PLAINS AND
RESULTANT ACCUMULATING SNOWFALL THE MAIN CONCERN. REGIONAL 88D MOSAIC
SHOWING BAND OF LIGHT SNOW ACTIVITY FROM ABOUT WEST CENTRAL IA TO NW
KS IN ASSOCIATION WITH LLVL ISENTROPIC UPGLIDE...PER LOWEST PROFILER
GATES AT KUEX AND FBYN1...JUST NORTH OF A STATIONARY SFC FRONT FROM
NRN IA TO S-CENTRAL KS. UP TOP...STRONG UPPER JET OVER 4 CORNERS
REGION FURTHER ENHANCING LIFT OVER THE REGION VIA STOUT 250MB-850MB
DIFFERENTIAL DIVERGENCE. MEANWHILE SFC OBS SHOWING STRONG PRESSURE
FALLS FOCUSED IN ERN KS/WRN MO IN RESPONSE TO APPROACHING UPPER
SHORTWAVE ENERGY. AT THIS POINT...PRETTY CLEAR THAT CWA WILL SEE
SIGNIFICANT SNOW ACCUMULATION TOTALS BY WEDNESDAY. FOR TONIGHT...
MODELS ARE IN GOOD AGREEMENT FORCING WITH ZIPPY LEAD SHORTWAVE WILL
BEGIN SUBSIDING AROUND 06Z WHEN BRUNT OF SYNOPTIC LIFT SHIFTS THE MID
MS VLY...THEN OH VLY/GREAT LAKES REGION BY 12Z MONDAY. GIVEN SPEEDY
NATURE OF THIS SYSTEM...EXPECT SNOW TOTALS WILL GENERALLY BE 1-2
INCHES WITH LOCALLY HEAVIER AMOUNTS LIKELY. ON MONDAY...COLDER AND
DRY CONDITIONS AS WEDGE OF SFC HIGH PRESSURE BUILDS SWD ALONG THE WRN
HIGH PLAINS. MEANWHILE...500MB HGT INCREASES OVER THE PLAINS WILL BE
SHORT LIVED WHEN SECOND POTENT SHORTWAVE OF CONCERN BOTTOMS OUT NEAR
THE 4 CORNERS REGION TUESDAY MORNING. IMPRESSIVE 500MB HGT FALLS
APPROACHING 20DAM PROGGED WITH THIS SYSTEM AS IT EJECTS INTO KS/OK
TUESDAY AFTN AND LIFTS THRU MID/UPPER MS VLY TUESDAY NIGHT. SFC
REFLECTION RESPONDS WITH SIGNIFICANT DEEPENING AS IT TRACK ALONG WITH
THE UPPER WAVE. AS OF NOW IT LOOKS LIKE AXIS OF HEAVIEST SNOWFALL
WILL MAINLY CUT THRU SE NEB AND SW IA GIVEN FOCUS OF MAX OMEGA...
GREATEST MID LYR TRANSVERSE AGEOSTROPHIC FORCING...FAVORABLE 500MB
HFC TRACK...AND LOCATION OF STRONGEST DENDRITIC LYR LIFT. GIVEN
ANTICIPATION OF BLOWING SNOW WITH THIS SECOND SYSTEM...PLAN ON
INCLUDING REMAINING 2 COUNTIES PREVIOUS LEFT OUT OF MID WEEK WINTER
STORM WATCH. ALSO PLAN ON ADDING REST OF OUR IOWA COUNTIES TO
WINTER ADVISORY IN EFFECT FOR TONIGHT.
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY.
AFTER THE SYSTEM MOVES OUT...ARCTIC AIR WILL PUSH IN BEHIND THE LOW
AND FILTER EAST THROUGH FRIDAY. THIS PORTION OF THE PD LOOKS
DRY...SO MAIN FCST CHALLENGE WILL BE HOW COLD IT WILL GET
TOWARDS THE END OF THE WEEK. TEMPS WILL ATTEMPT TO RECOVER AS THE
PATTERN MODERATES FROM NORTHWEST FLOW TO A MORE ZONAL FLOW INTO THE
WEEKEND...BUT WILL STAY BELOW AVERAGE DUE TO LINGERING SNOW COVER.
MOS GUIDANCE HAS TRENDED DOWNWARD ON HIGH TEMPS IN LAST COUPLE OF
FCST CYCLES...WHICH SEEMS TO BE A MOVE IN THE RIGHT DIRECTION...SO
HAVE STAYED RATHER CLOSE TO MOS TEMPS THROUGHOUT THE EXTENDED.
HOWEVER...AM NOT COMPLETELY ON BOARD WITH DRAMATIC DROP IN THURS
HIGHS IN LATEST GFS RUN...SO HAVE RAISED THOSE SLIGHTLY ABOVE
AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
AN AREA OF MODERATE SNOW WILL MOVE ACROSS THE TAF SITES THROUGH THIS
EVENING WITH MVFR PERIODS OF IFR CIGS AND VSBYS THROUGH 18Z. MOST
OF THE SNOW SHOULD END BTWN 06Z AND 09Z...HOWEVER THE CIGS WILL
REMAIN. IN ADDITION TO THE SNOW AND LOW CIGS...NORTHEAST WINDS AT
14 TO 24 KTS WILL SWING AROUND TO THE NORTH AND NW AND GENERALLY
DECREASE TO UNDER 15KTS AFT 09Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 3 AM CST MONDAY FOR NEZ015-034-045-
052-053-067-068.
WINTER STORM WATCH FROM LATE MONDAY NIGHT THROUGH LATE TUESDAY
NIGHT FOR NEZ011-012-015>018-030>034-042>045-050>053-
065>068-078-088>093.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ033-
043-044-050-051-065-066-078-088>093.
IA...WINTER WEATHER ADVISORY UNTIL 3 AM CST MONDAY FOR IAZ043-055-056-
069-079-080-090-091.
WINTER STORM WATCH FROM LATE MONDAY NIGHT THROUGH LATE TUESDAY
NIGHT FOR IAZ043-055-056-069-079-080-090-091.
&&
$$
SHORT TERM...MILLER
