FXUS63 KOAX 062020
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
320 PM CDT WED APR 6 2011
.SHORT TERM...TONIGHT THROUGH SATURDAY.
RAIN CHANCES THURSDAY AND EVOLUTION OF CONVECTION/WARM FRONT
POSITION FRIDAY NIGHT INTO SATURDAY MAIN FORECAST FOCUS IN SHORTER
TERM.
SURFACE FRONT WEDNESDAY AFTERNOON HAD PUSHED TO A WEST
CENTRAL MO TO TX PANHANDLE LINE WITH MODIFIED GULF AIR STILL SOUTH
OF OKLAHOMA AT 20Z. EASTERN SECTION OF FRONT IS FORECAST TO STALL OVER
OK BEFORE LIFTING TOWARD NERN KS/NWRN MO BY THURSDAY EVENING.
ISENTROPIC LIFT NEAR H7 WARM FRONT THAT WAS FORECAST TO LIFT
TOWARD SRN NEBRASKA THURSDAY WILL LIKELY INCREASE CLOUDS LATE
TONIGHT AND SPREAD PRECIP ACROSS THE FORECAST AREA THURSDAY.
HOWEVER...SEVERAL ITEMS WERE NOTED. ONE...TIME SECTIONS AT
FORECAST POINTS ACROSS ERN ZONES DID NOT SHOW DEEPER MOISTURE
ARRIVING UNTIL TOWARD THURSDAY EVENING. TWO...SURFACE DEW POINTS WILL
PROBABLY BE SLOW TO RECOVER AND THREE...ELEVATED INSTABILITY PER
FORECAST SOUNDINGS WAS EITHER ABSENT OR MINIMAL. SO MADE SEVERAL
ADJUSTMENTS. DOWNPLAYED CONVECTION AND LOWERED SOME POPS...
ESPECIALLY IN THE MORNING EAST. NONETHELESS...THE LIFT SHOULD BE
ENOUGH TO BRING WIDESPREAD CLOUDS BY AFTERNOON SO WOULD SUSPECT
MOST TEMPERATURES WOULD STRUGGLE TO GO ABOVE MAV GUIDANCE AND MANY
WERE LOWERED.
AFTER WEAK WAVE/ELEVATED WARM FRONT LIFTS NORTHEAST OF
AREA...RAIN/ISOLATED CONVECTION CHANCES SHOULD DECREASE OR END BY
FRIDAY MORNING AND FORECAST SOUNDINGS WERE EITHER ABSENT MOISTURE
OR CAPPED UNTIL MAX HEATING OR A BIT AFTER THAT ON SATURDAY. THUS
AFTER THURSDAY EVENING WOULD EXPECT LITTLE PRECIP CHANCES TILL
LATE SATURDAY AFTERNOON/EVENING...ALTHOUGH LEFT IN SOME SMALL POPS FAR
NRN/ERN ZONES FRI NIGHT AS LOW LEVEL JET INCREASES. MODELS WERE
INDICATING A LOT OF LOW CLOUDS WILL DEVELOP/EXIST BEHIND PRECIP
AREA THU NIGHT AND THEY COULD LIMIT HEATING ON FRIDAY PER NAM.
BECAUSE OF THAT RISK...MADE LITTLE TEMPERATURE CHANGES TO FRIDAY
...WITH SRN ZONES CLOSER TO WARMER GFS/MAV AND A BLEND OF THE COOLER
MET AND WARMER MAV ELSEWHERE. ON SATURDAY MODELS ALL INDICATED FRONT
SHOULD PUSH AT LEAST TO OMA/TQE AREA SATURDAY...WITH GEM/ECMWF
EVEN A BIT NORTH OF THERE. THUS...PULLED 80+ READINGS FARTHER NE.
STILL SOME LIKELIHOOD THAT A DOUBLE STRUCTURE TO FRONT WILL
EXIST...SHARPEST PROBABLY ACROSS OR NEAR NERN NEBRASKA WITH
SECONDARY ONE NEAR KS BORDER. EITHER BOUNDARY COULD BECOME ACTIVE
BUT WOULD EXPECT SRN ONE TO POSSIBLY IGNITE FIRST WITH HEATING
AIDED BY DRY LINE. STORMS COULD BECOME SEVERE AS BOTH GFS AND NAM
FORECAST 0-6KM SHEAR VALUES TO BE 55+KTS ACROSS SERN ZONES
CO-LOCATED WITH SURFACE BASED CAPE VALUES OF 2000 OR MORE J/KG.
WILL CONTINUE TO MENTION THIS IN HAZARDOUS WEATHER OUTLOOK.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY.
00Z ECMWF HAS COME AROUND CLOSER TO THE FASTER SOLUTION OF 12Z AND
EARLIER RUNS OF THE GFS REGARDING TROUGH/UPPER LOW AND FRONTAL
TIMING ON SUNDAY. HOWEVER...SINCE UPPER SYSTEM APPEARS IT WILL
CLOSE OFF...FRONT MAY NOT CLEAR FAR SERN ZONES UNTIL MID/LATE
SUNDAY AFTERNOON SO KEPT THAT AREA FAIRLY MILD...LOWER 70S WITH
HIGHEST THUNDERSTORM CHANCES. OTHERWISE CUT BACK ON TEMPERATURES
AS COLD ADVECTION/CLOUDS AND POST-FRONTAL SHOWERS SHOULD LIMIT
HEATING MOST AREAS. WITH GFS/ECMWF CLOSING UPPER SYSTEM OFF
BEFORE EJECTING IT EWD...A SOMEWHAT SLOWER PROGRESSION OF THE
NEXT UPSTREAM TROUGH/FRONT PER 00Z ECMWF WAS FOLLOWED. THUS
LINGERED SOME PRECIP CHANCES ACROSS THE ENTIRE FORECAST AREA
SUNDAY NIGHT AND HAD THE SECOND DAY AFTER...I.E. TUESDAY...THE
WARMEST DAY BEFORE THE NEXT UPPER TROUGH/FRONT CROSSES CENTRAL
PLAINS. CARRIED SMALL POPS ALONG WITH COOLER TEMPERATURES THEN
ON WEDNESDAY.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE PERIOD...BUT MVFR
CIGS MAY DEVELOP AFTER 12Z AS OVER RUNNING PATTERN DEVELOPS NORTH OF
A WARM FRONT OVER SOUTHERN KANSAS AND UPPER LEVEL WAVE LIFTS TOWARD
THE CENTRAL PLAINS IN ADVANCE OF WEST COAST TROUGH.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/FOBERT