FXUS63 KOAX 162043
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
343 PM CDT WED MAR 16 2011
.SHORT TERM...TONIGHT THROUGH SATURDAY
A MILD AND BREEZY AFTERNOON IS IN PROGRESS ACROSS THE CWA. THIS IS
OCCURRING AHEAD OF LOW PRESSURE ACROSS CENTRAL SOUTH
DAKOTA...ASSOCIATED WITH A POTENT UPPER LEVEL SHORTWAVE TROUGH
NOW OVER NORTHERN MT. THIS AREA OF LOW PRESSURE IS EXPECTED TO
TRACK EAST OVERNIGHT WITH THE SURFACE COLD FRONT DROPPING INTO THE
FA. AHEAD OF THE FRONT THOUGH...SOUTHERLY WINDS WILL CONTINUE
THROUGH THE NIGHT...LEADING TO A FAIRLY MILD NIGHT. LOW-LEVEL
MOISTURE WAS INCREASING THIS AFTERNOON OVER THE SOUTHERN PLAINS
AND THIS WILL LIKELY LEAD TO STRATUS RAPIDLY MOVING NORTHWARD
OVERNIGHT ACROSS THE EASTERN 2/3RD OF THE FA. HAVE KEPT SOME
MENTION OF DRIZZLE IN THESE AREAS.
AS THE NEXT UPSTREAM SYSTEM APPROACHES THE AREA /CURRENTLY COMING
ONSHORE OVER NORTHERN CA/ ON THURSDAY AFTERNOON...THE SURFACE COLD
FRONT WILL SHIFT THROUGH THE FA NEARING THE KS/NEB BORDER BY 00Z
FRIDAY. MOISTURE WILL CONTINUE TO INCREASE AHEAD OF THIS
FRONT...BUT POINT FORECAST SOUNDINGS INDICATE THAT THE ATMOSPHERE
THROUGH THE DAY WILL REMAIN CAPPED OVER SOUTHEAST NEBR AND SW IA
DUE TO LIMITED MOISTURE AND INCREASING MID-LEVEL TEMPERATURES. IT
SHOULD BE ANOTHER WARM DAY IN SOUTHEAST NEB AND SW IA...BUT COOLER
TEMPERATURES ARE EXPECTED ALONG AND NORTH OF INTERSTATE 80.
GENERALLY USED A MIX TO 900 MB THINKING OVER THE NORTHERN FA...BUT
MIXING TO NEAR 850 MB WILL BE POSSIBLE IN THE FAR SOUTH. MODEL
INCREASE FRONTOGENESIS ACROSS THE NORTHERN FA ON THURSDAY NIGHT
WITH CROSS SECTIONS INDICATING AN IMPRESSIVE FRONTAL CIRCULATION
DEVELOPING NEAR THE SD/NEB BORDER AFTER 06Z. LARGE-SCALE ASCENT IS
ONLY MODEST THOUGH AND MOISTURE APPEARS TO BE GENERALLY LACKING.
NEVERTHELESS WITH SUCH STRONG MESOSCALE FORCING WITH WEAK STATIC
STABILITY...SHOULD LEAD TO SHOWERS WITH MEASURABLE PRECIPITATION.
THUS HAVE INCREASED POPS IN THE FAR NORTHWEST CWA TO LIKELY ON
THURSDAY NIGHT AFTER 09Z. SOME SHOWERS SHOULD CONTINUE INTO FRIDAY
ALONG WITH A GOOD DEAL OF CLOUDS...BUT BOTH WILL DECREASE BY
AFTERNOON.
WE HAVE LOWERED GOING HIGHS ON FRIDAY AND SATURDAY GIVEN THE
EXPECTED CLOUD COVER AND COOL NORTHEAST SURFACE WINDS. STRONG LOW-
LEVEL WARM AIR ADVECTION AGAIN INCREASES DURING THE DAY ON
SATURDAY AND MODELS INDICATE DECENT ASCENT ON THE 295 K SURFACE
WHICH MAY LEAD TO A FEW SHOWERS THROUGH THE DAY...ESPECIALLY OVER
SOUTHEAST NEB AND WESTERN IA.
BOUSTEAD
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
MEDIUM RANGE MODELS CONTINUE TO SHOW A FAIRLY ACTIVE EXTENDED
PERIOD. SOUTHWEST UPPER LEVEL FLOW WILL BE UNDERWAY AS LARGE TROF
MOVES ONTO THE PACIFIC COAST. MINOR WAVES EJECTING OUT OF THE TROF
ARE DIFFICULT TO FORECAST AT THIS POINT SO CONFIDENCE ON EXTENDED
FORECAST IS FAIRLY LOW. LOW LEVEL SOUTHERLY FLOW SHOULD BE UNDERWAY
AS THE PERIOD BEGINS WITH A SFC LOW CENTERED IN THE HIGH PLAINS
REGION PLACING A WARM FRONT SOMEWHERE ACROSS THE CNTRL PLAINS
REGION. EXACTLY WHERE THIS FRONT WILL EXTEND ON SUNDAY IS
UNCERTAIN...BUT FORECAST INSTABILITY ALONG THE BOUNDARY DOES
CONTINUE TO WARRANT TSTM MENTION AS IT COULD EXTEND THRU THE
FORECAST AREA. POTENT UPPER TROF WILL MOVE INTO THE HIGH PLAINS
REGION LATE MONDAY. THERE CONTINUES TO BE MODEL DISAGREEMENT ON
PLACEMENT OF THIS FEATURE SO AGAIN...CONFIDENCE REMAINS LOW. THIS
FEATURE COULD BRING A MIX OF THUNDERSTORMS...RAIN AND MAYBE EVEN A
MIX OF WINTRY PCPN TO THE REGION. WL LEAVE THE WINTRY MIX OUT OF THE
FORECAST AT THIS POINT UNTIL MORE CERTAINTY IS SEEN IN THE MODEL
GUIDANCE.
KERN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS WILL CONTINUE AT ALL SITES THROUGH 06Z. AFTER
THEN...STRATUS WILL MOVE INTO THE CWA FROM SOUTH TO
NORTH...SPREADING MVFR TO IFR CIGS INTO KLNK/KOMA/KOFK PROGRESSIVELY
BETWEEN AROUND 08-10Z...AND CONTINUING THROUGH AROUND 18Z. VIS MAY
ALSO BE RESTRICTED TO AT LEAST MVFR. WINDS TONIGHT WILL LOSE
GUSTINESS AFTER 00Z...WITH WIND SPEEDS DECREASING TOWARD DAYBREAK
AND VEERING TO SOUTHWESTERLY AS A COLD FRONT APPROACHES.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$