FXUS63 KOAX 040819
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
319 AM CDT WED MAY 4 2011
.DISCUSSION...
QUIET WEATHER AND DRY AIRMASS REMAINS IN PLACE...THOUGH PATTERN
BECOMES MORE ACTIVE FOR THE REST OF THE WEEK AND INTO THE WEEKEND.
SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES WAVY UPPER-LEVEL
PATTERN...WITH TROUGH ACROSS THE ROCKIES...RIDGE ACROSS THE CENTRAL
PLAINS...AND TROUGH OVER THE GREAT LAKES/MISSISSIPPI RIVER VALLEY.
AREA RAOBS INDICATE DRY AIRMASS IS STILL ENTRENCHED OVER THE
PLAINS...THOUGH TEMPERATURES ARE MODERATING IN WAKE OF THE 850MB
RIDGE AXIS EXTENDING FROM MN TO TX. 07Z SURFACE ANALYSIS INDICATES
DOUBLE LOW CENTERS...ONE IN WESTERN SD AND THE OTHER IN EASTERN
CO...WITH TIGHTENING PRESSURE GRADIENT ACROSS THE PLAINS AS WELL AS
INCREASING MID-LEVEL CLOUDS AROUND 10KFT.
MAIN FORECAST CONCERNS ARE SHOWER/THUNDER POTENTIAL WITH FRONTAL
PASSAGE TONIGHT...THEN INTERMITTENT CHANCES FOR SHOWERS OR
THUNDERSTORMS THROUGH THE WEEKEND. THINK MOST OF TODAY WILL BE DRY
AS MOISTURE IS MEAGER AND FORCING IS AWAY TO THE WEST/NORTHWEST.
POTENT UPPER-LEVEL WAVE SHOULD EVENTUALLY CREATE ENOUGH FORCING TO
OVERCOME THE MOISTURE DEFICIT AND ALLOW SHOWERS/THUNDER TO DEVELOP.
PROGS DO INDICATE SOME INSTABILITY...BUT KEPT THUNDER TO ISOLATED
MENTION AS LACK OF MOISTURE WILL IMPEDE INSTABILITY. AFTER
MIDNIGHT...INSTABILITY WEAKENS ENOUGH TO KEEP THUNDER OUT OF THE
GRIDS...THOUGH SHOWER COVERAGE SHOULD INCREASE THROUGH THE NIGHT AS
THE COLD FRONT MOVES THROUGH. OVERALL...EXPECT LIGHT PRECIP AMOUNTS
AND STILL HAVE SOME CONCERNS ABOUT COVERAGE...BOTH DUE TO DRY
AIRMASS IN PLACE...AND HAVE REMAINED FAIRLY CONSERVATIVE WITH POPS.
DID BUMP UP TEMPS A BIT FOR TODAY GIVEN STRONG SOUTHERLY FLOW THAT
WILL PROVIDE GOOD MIXING...AS WELL AS DRY AIRMASS THAT WILL BE
CONDUCIVE TO STRONGER WARMING.
UPPER-LEVEL TROUGH CONTINUES TO MOVE ACROSS THE NORTHERN PLAINS INTO
THE GREAT LAKES ON THURSDAY. TEMPS WILL BE A BIT COOLER THAN
TODAY...BUT STILL SHOULD BE ENOUGH MIXING TO BE WELL INTO THE 60S.
DID CONTINUE SLIGHT CHANCE FOR SHOWERS IN THE AFTERNOON AS POCKET OF
HIGHER LAPSE RATES/UPPER-LEVEL COLD AIR FOLLOWS THE TROUGH...THOUGH
DID REMOVE THUNDER. ALSO BUMPED UP CLOUDS. AGAIN...LACK OF
MOISTURE IS THE MOST LIKELY LIMITING FACTOR...AND MIGHT LIMIT ANY
SHOWERS TO JUST SPRINKLES. ANY SHOWERS SHOULD DIE AWAY QUICKLY ON
THURSDAY EVENING...WITH A QUIET AND COOL THURSDAY NIGHT...AND NUDGED
TEMPS DOWNWARD A COUPLE OF DEGREES.
RETURN TO STRONG SOUTHERLY FLOW AHEAD OF NEXT FRONT...ALONG WITH
MID-LEVEL WARM AIR ADVECTION...SHOULD ALLOW STRONG WARMING ON
FRIDAY...AND HAVE PUSHED TEMPS WELL INTO THE 70S ACROSS THE AREA.
AGAIN...MOISTURE REMAINS LIMITED AS A HIGH LINGERS OVER THE NORTHERN
GULF OF MEXICO...THOUGH MOISTURE WILL BE INCREASING THROUGH THE DAY
ON FRIDAY. KEPT A SLIGHT CHANCE OF SHOWERS/THUNDERSTORMS IN THE
EASTERN CWA ON FRIDAY AFTERNOON JUST AHEAD OF THE NEXT SURFACE LOW
MOVING ACROSS THE CWA...BUT HAVE FOLLOWED THE FASTER ECMWF SOLUTIONS
THAT PUSH CONVECTION WELL OFF TO THE EAST/SOUTHEAST ON FRIDAY
EVENING...AND KEPT THE CWA DRY FOR THE EVENING AND OVERNIGHT.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
SOUTHEAST WINDS AHEAD OF A COLD FRONT WILL BE THE INITIAL AVIATION
CONCERN...AROUND 12KT AT OFK EARLY THIS MORNING WITH GUSTS UP TO
18KTS. WINDS SHOULD INCREASE AT ALL TAF SITES BY 14Z TO AROUND 18KTS
WITH GUSTS TO 26-30KTS THROUGH 05/02Z. OTHERWISE...VFR CONDITIONS
PREVAIL. COLD FRONT IS FORECAST TO ARRIVE AT KOFK BY 23Z WITH A WIND
SHIFT TO THE NORTHWEST...AND ALSO A CHANCE FOR SHOWERS AND
THUNDERSTORMS. FRONTAL PASSAGE NEAR KOMA/KLNK BY 05/02Z. HAD SOME
DOUBT WHETHER CONVECTION WOULD MAKE IT AS FAR SOUTH AS LINCOLN...
THUS LEFT MENTION OUT OF THE FORECAST AT THIS TIME.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
MAYES/DEWALD