FXUS63 KOAX 231637 AAA
AFDOAX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1137 AM CDT MON MAY 23 2011
.UPDATE...
SMALL BAND OF SHOWERS THAT WAS OVER PARTS OF THE AREA EARLIER THIS
MORNING HAS DISIPATED. MADE SOME MINOR ADJUSTMENTS TO PRECIPITATION
CHANCE FOR THIS AFTERNOON AND CARRIED THESE INTO THE EVENING. A FEW
SHOWERS AND THUNDERSTORMS MAY POP UP THIS AFTERNOON AS THE
ATMOSPHERE DESTABILIZES. ANY STORMS THAT DO DEVELOP SHOULD WEAKEN
EARLY THIS EVENING.
MILLER
&&
.PREV DISCUSSION... /ISSUED 312 AM CDT MON MAY 23 2011/
DISCUSSION...
MID WEEK RAIN CHANCES ARE THE PRIMARY FORECAST CONCERNS.
UPPER LOW THAT CAUSED OUR SEVERE WEATHER SATURDAY AND MORE SEVERE
FOR THE NORTHERN PLAINS ON SUNDAY WAS SPINNING INTO WISCONSIN THIS
MORNING...AND WILL CONTINUE ITS TREK THROUGH THE NORTHERN GREAT
LAKES TODAY. THIS LEAVES OUR AREA UNDER WEAK WEST OR NORTHWEST FLOW
ALOFT AND NO SIGNIFICANT FEATURES ON WHICH TO BASE PRECIPITATION
CHANCES. AN 850 MB BAROCLINIC ZONE IN OUR SOUTH THIS MORNING IS
FORECAST TO SINK SOUTH...OTHERWISE ONLY WEAK NORTHERLY FLOW FOR MOST
OF THE CWA. MODELS HINT AT A WEAK CONVERGENCE ZONE IN SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA THIS AFTERNOON...AND TEMPERATURES ALOFT
ARE COOL. SPORADIC PRECIPITATION SIGNALS ON SHORT-RANGE MODELS
INDICATE A SMALL CHANCE FOR POPCORN SHOWERS THIS AFTERNOON. AND
THERE IS WEAK INSTABILITY UNDER COOL MID LEVEL TEMPS. WHILE I CAN
NOT RULE OUT A HIT AND MISS SHOWER...THINK CHANCES ARE TOO LOW TO
MENTION EXCEPT IN THE FAR NORTH AND FAR SOUTH PARTS OF THE CWA.
ATTENTION THEN TURNS TO NEXT UPPER LOW/TROUGH THAT WILL MOVE INTO
THE PLAINS TUESDAY AND WEDNESDAY. WATER VAPOR LOOPS SHOW THE
BEGINNINGS OF THIS FEATURE RACING SOUTHEAST...WEST OF THE NORTHERN
CALIFORNIA COAST...INDICATED BY A CURL OF DARKENING ON THE IMAGERY.
THIS FEATURE WILL SWING THROUGH SOUTHERN CALIFORNIA TODAY THEN MOVE
EAST OF THE FOUR CORNERS REGION ON TUESDAY. STRONG SOUTHWEST FLOW
AHEAD OF IT WILL ENHANCE SURFACE CYCLOGENESIS IN THE SOUTHERN HIGH
PLAINS...WHICH IN TURN WILL ACCELERATE SOUTHERLY FLOW FROM TEXAS
INTO KANSAS. SURFACE FRONT WILL SHARPEN ACROSS NORTHERN KANSAS
TUESDAY...THEN COULD LIFT INTO SOUTHEAST NEBRASKA TUESDAY NIGHT.
THIS WOULD ENHANCE SEVERE THREAT THERE...BUT MODELS DIFFER ON
NORTHWARD PUSH OF WARM FRONT. WHAT LOOKS CERTAIN IS STRONG THETA-E
ADVECTION TUESDAY AFTERNOON AND NIGHT ACROSS A GOOD PART OF NEBRASKA
AND WESTERN IOWA WHERE LOW LEVEL JET ACCELERATES UNDER DIFFLUENT
FLOW ALOFT. A CLASSIC ISENTROPIC UPGLIDE SITUATION SHOULD ENSUE
WHICH WILL DROP POTENTIALLY HEAVY AMOUNTS OF RAIN OVER OUR CWA...AND
ELEVATED HAIL STORMS ARE ALSO POSSIBLE. ONLY REAL QUESTIONS ARE
WHERE EXACTLY WILL AXIS OF HEAVIEST RAIN SET UP...AND WILL SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA SEE REDUCED RAINFALL DUE TO DRY SLOT.
DESPITE SOMEWHAT DIFFERENT INITIAL SURFACE LOW POSITIONS IN THE HIGH
PLAINS...THE GFS AND NAM BOTH MOVE SURFACE LOW INTO NORTH CENTRAL
KANSAS BY WEDNESDAY MORNING...AND HAVE SIMILAR IDEAS ON
PRECIPITATION PLACEMENT. THIS LENDS SOME DEGREE OF CONFIDENCE THAT
THE MAJORITY OF THE CWA WILL SEE OVER AN INCH OF RAIN TUESDAY NIGHT
WITH SOUTHEAST NEBRASKA THE LIGHTEST.
RAIN WILL CONTINUE ON WEDNESDAY IN DEFORMATION ZONE NORTH AND
NORTHWEST OF UPPER LOW MOVING THROUGH EASTERN KANSAS. AGAIN HEAVY
RAIN IS POSSIBLE. INTENSITY AND CHANCES FOR RAIN WILL DECREASE
WEDNESDAY NIGHT AS LOW MOVES OFF TO THE SOUTHEAST.
NEXT CHANCE FOR RAIN/STORMS STILL LOOKS TO BE FRIDAY AS UPPER
LOW/TROUGH MARCHES THROUGH THE NORTHERN PLAINS. GFS DEPICTION IS
FARTHER NORTH THAN 24 HOURS AGO...BUT STILL PAINTS QPF IN THE AREA.
WILL CONTINUE WITH LOW CHANCE POPS THEN.
TEMPERATURES WILL START THE WEEK IN THE 70S TO NEAR 80 MONDAY AND
THEN AGAIN TUESDAY BEFORE RAIN...CLOUDS AND NORTH TO NORTHEAST LOW
LEVEL FLOW TAKE OVER WEDNESDAY. HIGHS THEN WILL ONLY BE IN THE 50S
AND 60S. A LITTLE WARMER THURSDAY DESPITE COOLER 850 TEMPERATURES AS
SUNSHINE RULES. EXPECT TEMPERATURES IN THE 70S...OR PERHAPS
WARMER...FOR THE WEEKEND.
DERGAN
AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
AREA BETWEEN SPLIT UPPER FLOW FOR THE FORECAST PERIOD WITH LINGERING
WAVE IN THE NORTHERN FLOW MOVING EAST DURING THE DAY FOLLOWED BY
SHORT WAVE RIDGE. VFR CONDITIONS EXPECTED THROUGH THE PERIOD WITH
SOME MID LEVEL CIGS AT TIMES.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$