741
FXUS63 KOAX 042019
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
319 PM CDT SAT JUL 4 2009
SHORT TERM
TONIGHT THROUGH TUESDAY. SURFACE LOW ACROSS
NORTHWEST MISSOURI WILL HAS BEEN SLOW TO PULL AWAY FROM THE
REGION. IN AN INVERTED TROUGH THAT EXTENDS NORTHWARD THROUGH THE
MISSOURI RIVER VALLEY...AN IFR STRATUS DECK THIS MORNING HAS NOW
LIFTED INTO AN MVFR STRATOCU DECK THIS AFTERNOON. COULD EVEN BE A
FEW SPITS OF LIGHT RAIN HITHER AND YON THROUGH LATE AFTERNOON...BUT
NO NEED TO MENTION FOR THE TONIGHT PORTION OF THE FORECAST. LOW
LEVEL MOISTURE PROGS...AS WELL AS BUFKIT SOUNDINGS...SUGGEST THAT
CLEARING/SCATTERING SHOULD TAKE PLACE TONIGHT THROUGH THE NIGHT...
WITH DIMINISHING WINDS AS WELL. DEWPOINTS DO NOT APPEAR TO BE
SUFFICIENTLY SCRUBBED CLEAN OVERNIGHT...THUS WITH ALL THINGS
COMBINED... COULD SEE SOME PATCHY FOG DEVELOP OVERNIGHT ALTHOUGH
NOTHING TOO SERIOUS.
THEREAFTER...HAVE SOMEWHAT LOW CONFIDENCE IN THE FORECAST AS THE
MODELS SEEM TO BE OUT OF SYNC REGARDING SYNOPTIC FEATURES AND
AREAL PLACEMENT OF PRECIPITATION. HIGH PRESSURE BUILDING ACROSS
THE MISSOURI VALLEY SUNDAY SHOULD HELP TO SUPPRESS PRECIP IN OUR
AREA...ALTHOUGH PERHAPS THE NAM MIGHT HAVE THE BEST HANDLE HERE
WITH A SMALL PRECIP CHANCE TO OUR NORTH AS A WEAK FRONT TRIES TO
SETTLE SOUTHWARD. CAN'T REALLY SEE OR UNDERSTAND THE PRECIP THREAT
AS DEPICTED BY THE GFS/ECMWF ACROSS OUR CWFA...THUS HAVE REMOVED
POPS FOR SUNDAY AFTERNOON. TEMPS SHOULD REBOUND THOUGH INTO THE
LOWER 80S FOR A TYPICAL SUMMERTIME DAY.
MODELS SHOW NO DISCERNIBLE WAVE MOVING OFF THE HIGH PLAINS SUNDAY
NIGHT THROUGH MONDAY...THUS HAVE OPTED TO REMOVE POPS FROM THIS
TIME PERIOD. GIVEN LACK OF STRONG SIGNAL WITH MODELS...DECIDED TO
KEEP THIS PERIOD DRY TOO UNTIL SOMETHING BETTER DEFINED APPEARS IN
THE PROGS.
FOR MONDAY NIGHT/TUESDAY...BELIEVE THE NAM HAS DEPARTED FROM THE OTHER
MODEL SUITES IN ITS DEPICTION OF DRIVING A NEW FRONT SOUTHWARD INTO
THE AREA OUT OF SOUTH DAKOTA...WHILE THE GFS/ECMWF KEEP A SOUTHERLY
FLOW PREVAILING WITH WARMING TEMPS. THUS...WILL CONTINUE TO KEEP
THINGS ON THE DRY SIDE WITH TEMPS RETURNING TO SLIGHTLY ABOVE
NORMAL IN THE UPPER 80S AND LOWER 90S.
BY TUESDAY NIGHT...BOTH THE GFS/ECMWF NOW SUGGEST THAT A VERY
SUBTLE WAVE COULD DRIFT THROUGH THE FORECAST AREA...BUT GIVEN THE
MODELS LOW TRACK RECORD FOR THIS TYPE OF EVENT...DECIDED TO KEEP
THINGS DRY AGAIN SINCE THE MODELS ARE SLIGHTLY OUT OF PHASE WITH
ONE ANOTHER REGARDING AREAL PLACEMENT.
LONG TERM
WEDNESDAY THROUGH SATURDAY. THE PERIOD WILL BE
CHARACTERIZED BY A RIDGE ACROSS THE SOUTHERN PORTIONS OF THE
ROCKIES AND PLAINS...BUT THE MODELS ARE ADVERTISING A FRONT THAT
IS EXPECTED TO MOVE INTO THE VICINITY BY THURSDAY AND THEN STALL
ACROSS THE AREA THROUGH THE REMAINDER OF THE FORECAST. WHILE THE
GFS AND ECMWF ARE SIMILAR IN THEIR SYNOPTIC LARGE SCALE FEATURES...
THEY DO DIFFER ON HOW FAR SOUTH THE FRONT MAKES IT AND RESULTANT
PRECIPITATION TRENDS. FOR NOW...HAVE FOLLOWED THE HPC GUIDANCE
FAIRLY CLOSELY BECAUSE OF THE MODEL DIFFERENCES. THIS WOULD KEEP
WEDNESDAY DRY...BUT BRING PRECIP CHANCES BACK TO THE FORECAST FOR
THURSDAY NIGHT THROUGH SATURDAY AS THE FRONT IMPACTS THE CWFA.
SHOULD BE HOT EARLY IN THE PERIOD...BUT THEN A SLIGHT COOL DOWN AS
THE FRONT SETTLES SOUTHWARD INTO THE MID MISSOURI RIVER VALLEY.
AVIATION
FOR TAF SITES KOFK/KOMA/KLNK FORECAST VALID THROUGH 05/18Z.
EARLY IN THE FORECAST PERIOD THE MAIN AVIATION CONCERN IS CEILING
HEIGHTS...AS MUCH OF EASTERN NEBRASKA IS CURRENTLY COVERED BY
PERSISTENT LOW CLOUDS. CURRENTLY HAVE MVFR CEILINGS AT KOFK TILL
22Z AND AT KLNK AND KOMA TILL 00Z...AFTER WHICH VFR CONDITIONS
SHOULD RETURN. AN AREA OF HIGH PRESSURE IS FORECAST TO MOVE
SOUTHEAST OUT OF THE DAKOTAS...FORCING THE SURFACE LOW OVER
NORTHWEST MISSOURI AND THE ASSOCIATED CLOUD COVER TO MOVE OUT OF
THE REGION. THE HIGH SHOULD BE OVER MUCH OF NEBRASKA BY
06Z...RESULTING IN PARTLY CLOUDY TO CLEAR SKIES...AND LIGHT WINDS
ACROSS THE REGION OVERNIGHT. BECAUSE OF THE CLEARING SKIES AND
LIGHT WINDS...THE DEVELOPMENT OF FOG WILL BE A
POSSIBILITY...BRINGING MVFR CONDITIONS TO ALL SITES. HAVE FIRST
MENTION OF FOG AT KLNK BEGINNING NEAR 07Z...FOLLOWED BY KOFK AT
08Z...AND KOMA AT 09Z. CURRENTLY HAVE VFR CONDITIONS RETURNING
AROUND 13 TO 14Z.
OAX WATCHES/WARNINGS/ADVISORIES
NE...NONE.
IA...NONE.
DEWALD
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