FXUS63 KOAX 272117
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
317 PM CST SAT NOV 27 2010
.SHORT TERM...TONIGHT THRU TUESDAY
UPPER RIDGE AXIS CONTINUES TO MOVE OVER THE CNTRL CONUS THIS
AFTERNOON WHILE SOUTHWESTERLY FLOW NEAR THE SFC HAS ALLOWED TEMPS
TO JUMP INTO THE LOWER 50S ACROSS MUCH OF THE CWA THIS AFTERNOON.
UPSTREAM...UPPER TROF AXIS HAS NOW MOVED ONTO THE PACIFIC COAST
AND WILL CONTINUE TO DIG AS IT PROGRESSES EWD OVER THE NEXT COUPLE
OF DAYS. IN ADVANCE OF THIS...SOUTHERLY FLOW ACROSS THE FORECAST
AREA WILL CONTINUE TO INCREASE AS AREA OF LOW PRESSURE OVER
EASTERN COLORADO BROADENS AND BEGINS TO PUSH EWD INTO THE CNTRL
PLAINS. WINDS SUNDAY COULD APPROACH WIND ADVISORY CRITERIA ACROSS
A FEW COUNTIES IN OUR FAR SWRN CWA. WL LET NEXT SHIFT DECIDE
TIMING AND AREAL COVERAGE AND EVEN IF A HEADLINE IS NEEDED.
DESPITE MILD TEMPERATURES ON SUNDAY...STRONG SERLY WINDS WL MAKE IT
FEEL FAIRLY BRISK. WILL HAVE HIGHS RANGING FROM THE LOWER 50S IN THE
SOUTH TO A FEW UPPER 40S IN THE NORTH WHERE FILTERED SUNSHINE COULD
BE AN ISSUE. CLOUDS WL CONTINUE TO THICKEN FROM NORTHWEST TO
SOUTHEAST THROUGH THE OVERNIGHT HOURS INTO MONDAY MORNING WHILE LEAD
PIECE OF ENERGY EJECTS OUT INTO CNTRL NEB/SD. LARGE SCALE FORCING
AHEAD OF THIS WAVE COULD BE ENOUGH TO BEGIN PCPN ACROSS OUR NRN
COUNTIES WITH SOME FREEZING DRIZZLE POSSIBLE INTO EARLY MONDAY
MORNING AHEAD OF STRONG COLD FRONT QUICKLY PROGRESSING EWD.
ISENTROPIC UPGLIDE AHEAD OF THE BOUNDARY WITH STRONG 850MB LLVL JET
ON THE ORDER OF 50-60KTS COULD PROVIDE ENOUGH LIFT FOR A FEW
SCATTERED RAIN SHOWERS. LIMITING FACTOR WILL BE MOISTURE SO HAVE
LEFT POPS FAIRLY LOW TO ACCOUNT FOR THIS IN OUR EAST.
FORECAST GETS A BIT MESSY MONDAY WITH FALLING TEMPERATURES THROUGH
THE DAY IN ASSOCIATION WITH FROPA. IN ADDITION...BETTER FORCING
REMAINS FAR TO OUR NORTH GIVING US WEAK CHANCES FOR PCPN ACROSS
THE FORECAST AREA. WL CONTINUE WITH HIGHEST CHANCE POPS ACROSS OUR
NORTH WHERE TEMP PROFILE SUPPORTS SNOW THROUGHOUT THE ENTIRE
EVENT. COULD SEE SOME LIGHT ACCUMULATIONS...LESS THAN HALF INCH OR
SO. STRONG NORTHWEST WINDS COULD PRODUCE SOME AREAS OF BLOWING
SNOW WITH THIS BUT AGAIN...ACCUMULATIONS LOOK TO REMAIN LIGHT SO
AM NOT TO EXCITED ABOUT IT YET. FARTHER SOUTH...WE COULD LIKELY SEE A
MIX OF PCPN TYPES BEFORE CHANGING OVER TO ALL LIGHT SNOW...WITH
PERIODS OF FREEZING DRIZZLE FOR A BRIEF TIME. AS MENTIONED
EARLIER...NORTHWEST WINDS BEHIND THE FRONT WL BE QUITE STRONG WITH
NEARLY 45 TO 50KTS SHOWN AT 850MB. WL LIKELY GUST TO NEAR 40 MPH
AT THE SFC OVERNIGHT MON INTO TUESDAY WHICH WOULD REDUCE WIND
CHILL VALUES TO THE SINGLE DIGITS BELOW ZERO ACROSS OUR NORTHERN
COUNTIES TUE MORNING.
AS SYSTEM EXITS TUESDAY MORNING...A FEW LINGERING LIGHT SNOW SHOWERS
ARE POSSIBLE ACROSS OUR WESTERN IOWA COUNTIES BUT SHOULD QUICKLY
MOVE OUT BY LATE MORNING. TUESDAY LOOKS CONTINUED COLD WITH WAA
MOVING IN BY WEDNESDAY.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
MID TROPOSPHERIC TROUGH SHOULD BE OFF TO OUR EAST AT THE BEGINNING
OF THIS PERIOD WITH HIGH PRESSURE BUILDING IN AT THE SURFACE. THIS
WILL SHIFT EAST THROUGH MID WEEK WITH TEMPERATURES THE MAIN CONCERN.
BY LATE THURSDAY LOW PRESSURE WILL BE DEVELOPING OVER THE ROCKIES
AND SOUTHERLY LOW LEVEL FLOW SHOULD STRENGTHEN. HIGHS SHOULD ONLY BE
IN 30S WEDNESDAY BUT REACH THE 40S ON THURSDAY AND POSSIBLY FRIDAY...
BUT HIGHS FRIDAY WILL PARTIALLY DEPEND ON CLOUD COVER. THERE IS SOME
POTENTIAL FOR PCPN...BUT AT THIS POINT HAVE DECIDED TO LEAVE POPS AT
14 OR LESS FRIDAY. THE 00Z RUN OF THE ECMWF INDICATED A SLIGHTLY
HIGHER POTENTIAL FOR PCPN AND A STRONGER SURFACE LOW THAN THE 12Z
ECMWF...12Z GFS AND OTHER RECENT RUNS OF THE GFS. IT DOES NOT LOOK
LIKE SIGNIFICANT MOISTURE GETS TAPPED UNTIL THE SYSTEM IS EAST OF
OUR AREA. THE BEST BET FOR MEASURABLE SNOW SHOULD STAY TO OUR NORTH
ACROSS THE DAKOTAS AND MINNESOTA.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
WINDS WILL BE THE PRIMARY AVIATION CONCERN THROUGH THE PD WITH VFR
CONDITIONS.
SURFACE HIGH PRESSURE OVER IOWA AND MISSOURI WILL CONTINUE TO GIVE
WAY AS SURFACE LOW PRESSURE DEVELOPS OVER THE WESTERN HIGH PLAINS.
THE LOW LEVEL JET WILL STRENGTHEN OVER THE PLAINS THIS
EVENING...ENOUGH TO INCLUDE LLWS FL015-020 AT 45-55KTS IN THE TAFS
STARTING AT 03Z AND CONTINUING THRU SUNDAY MORNING. SFC WINDS
TONIGHT SHOULD BE AROUND 10-15KT...HOWEVER WILL BEGIN TO MIX DOWN
AFT 12Z WITH 12-24KTS SUSTAINED AND GUSTS 20-30KTS THRU 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
KERN/MILLER/ZAPOTOCNY