FXUS63 KOAX 092028
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
328 PM CDT MON MAY 9 2011
.SHORT TERM...TONIGHT
THE MAIN CONCERNS TONIGHT WILL BE THE TEMPERATURES AND THE WINDS.
SURFACE LOW PRESSURE OVER WESTERN NEBRASKA AND EASTERN COLORADO WILL
MOVE INTO SOUTH DAKOTA OVERNIGHT...WITH THE FORECAST AREA REMAINING
IN THE MILD AIR. MUCH DRIER AIR HAS WORKED INTO THE ALBION AREA
WHERE SURFACE DEWPOINTS DROPPED INTO THE 30S WITH THE MIXING TODAY
WITH TEMPERATURES IN THE UPPER 90S. THE SOUTHEAST TO SOUTHEAST
WINDS OF 5 TO 15 MPH SHOULD KEEP TEMPERATURES FROM DROPPING OFF AND
WHEN WINDS DECREASE SURFACE DEWPOINTS SHOULD COME UP. FOR NOW HAVE
LOWS IN THE UPPER 50S TO UPPER 60S. COULD SEE SOME PATCHY FOG IN THE
MORNING ALTHOUGH AM COUNTING ON ANY FOG TO BE MINOR AS EXPECT THE
LOW LEVEL WINDS TO KEEP UP.
ZAPOTOCNY
.LONG TERM...TUESDAY THROUGH MONDAY
MAIN CONCERN THIS PERIOD WILL BE CONVECTIVE CHANCES ON TUESDAY
NIGHT THROUGH THURSDAY.
INITIAL POTENT CLOSED MID LEVEL CIRCULATION WITHIN THE MAIN UPPER
LEVEL MEAN WESTERN US TROUGH WILL BE EJECTING NORTHEAST THROUGH
THE WESTERN DAKOTAS ON TUESDAY. SURFACE DRY LINE SHOULD BE JUST
WEST OF OUR FORECAST AREA AROUND 12Z...BUT START TO MIX EAST
THROUGH THE MORNING AS THE SURFACE LOW /ASSOCIATED WITH THIS
INITIAL SYSTEM/ SHIFTS EAST INTO MINNESOTA. SURFACE WINDS WILL
BECOME SOUTHWEST THROUGH MID MORNING AND TEMPS SHOULD QUICKLY
RESPOND. MODELS THOUGH HAVE BEEN TRENDING WITH A LITTLE QUICKER
WITH THE MOVEMENT OF THIS INITIAL UPPER LEVEL SYSTEM AND THUS THE
DRY LINE BY AFTERNOON STALLS OVER THE SOUTHERN CWA...AND BY LATE
AFTERNOON MAY START TO SLOWLY BACK-UP AND BECOME LESS DEFINED.
THIS HAS AN IMPACT ON OUR TEMPERATURE FORECAST FOR TUESDAY. MIXING
IS EXPECTED TO BE STRONG...BUT WITH A LITTLE MORE BOUNDARY LAYER
MOISTURE IN PLACE...AND 850 MB TEMPERATURES A LITTLE COOLER...WE
MAY NOT SEE THE NEAR RECORD HIGHS OF TODAY. WE ARE STILL EXPECTING
READINGS NEAR 90 THOUGH IN PLACES. OTHERWISE CONVECTIVE CHANCES
APPEAR TO BE MINIMAL AGAIN TOMORROW WITH A DIFFUSED DRY LINE AND
LACK OF SIGNIFICANT UPPER LEVEL SUPPORT. BETTER MIXING LEADING TO
STEEPER LOW LEVEL LAPSE RATES...BETTER LOW-LEVEL CONVERGENCE AND
WEAKER CIN OVER PARTS OF ERN KS TUES AFTN MAY ALLOW FOR AN ISO
TSRA TO DEVELOP BY LATE AFTN TO OUR SOUTH...AND WILL INCLUDE A
VERY SMALL POP ON TUESDAY EVENING IN THE SOUTH IN CASE ANY OF THIS
ACTIVITY MAKES IT INTO FAR SE NEB BEFORE DISSIPATING WITH THE LOSS
OF DAY TIME HEATING.
SURFACE COLD FRONT ASSOCIATED WITH THE INITIAL NORTHERN PLAINS
CLOSED SYSTEM WILL MAKE A PUSH INTO OUR NORTHWEST FORECAST AREA ON
TUESDAY AFTERNOON AND CONTINUED TO SLOWLY SAG SOUTH ON TUESDAY
NIGHT BEFORE STALLING ALONG A LINE FROM ONAWA TO AROUND YORK. HAVE
LOWERED OVERNIGHT LOWS TO THE NORTH OF THIS BOUNDARY. DEEPER LOW
LEVEL MOISTURE WILL MAKE AN ATTEMPT TO RETURN TO THE REGION ON
TUESDAY NIGHT. THIS MAY LEAD TO A FEW LATE NIGHT SHOWERS OR STORMS
MAINLY OVER THE SOUTHERN FA. THE SOUTHERN STREAM UPPER LEVEL STORM
SYSTEM WILL THEN MAKE A TRACK FOR THE HIGH PLAINS DURING THE DAY
ON WEDNESDAY. MOST MODELS INDICATE THAT THE STALLED BOUNDARY
ACROSS THE FORECAST AREA WILL ATTEMPT TO SLOWLY LIFT BACK NORTH
THROUGH THE CWA DURING THE DAY. WITH DEEPER MOISTURE IN PLACE
BENEATH THE STEEP-LEVEL LAPSE RATES /ALREADY IN PLACE TODAY/...THE
ATMOSPHERE SHOULD BECOME MODERATELY TO STRONGLY UNSTABLE WITH
2000-3000 J/KG OF MLCAPE BY EARLY AFTERNOON. GIVEN THE LARGE-SCALE
FORCING FOR ASCENT AND COOLING MID-LEVEL
TEMPERATURES...THUNDERSTORM DEVELOPMENT IS EXPECTED DURING THE
AFTERNOON ALONG THE RETREATING FRONT AND TO THE SOUTHWEST OF OUR
FA ALONG THE ADVANCING DRY LINE. THE UPPER LEVEL JET DOES EJECT
BEHIND THESE SURFACE FRONTAL SYSTEM THOUGH...SO DEEP-LAYER SHEAR
IS A LITTLE LACKING...BUT SHOULD BE SUFFICIENT FOR SOME SEVERE
STORMS. CONVECTION SHOULD CONTINUE ON WEDNESDAY NIGHT AS THE UPPER
LEVEL SYSTEM APPROACHES THE AREA AND WE HAVE CATEGORICAL POPS
GOING.
WE PREFER THE SLOWER EC/NAM LOOK TO THE UPPER LEVEL LOW FOR
THUR/FRI WHICH KEEPS THE CHANCE OF PRECIP AROUND AND COOLER
TEMPERATURES. THE SYSTEM WILL FINALLY LOSE HOLD OF THE REGION BY
THE WEEKEND...WITH TEMPERATURES WARMING TO NEAR SEASONABLE LEVELS
BY THE LATE WEEKEND. WE LEFT THE EXTENDED DRY AFTER FRIDAY WITH
UPPER LEVEL RIDGING ADVANCING OVER AT LEAST THE HIGH PLAINS.
BOUSTEAD
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
AN AREA OF LOW PRESSURE OVER EASTERN COLORADO WILL TRACK INTO
SOUTHEAST SOUTH DAKOTA THROUGH TUESDAY MORNING. THERE MAY BE SOME
PATCHY MVFR CONDITIONS WITH FOG TUESDAY MORNING...OTHERWISE VFR
CONDITIONS WILL CONTINUE THROUGH THE PERIOD.
SOUTHEAST TO SOUTHWEST SURFACE WINDS AT 10 TO 20KTS SUSTAINED WITH
GUSTS 20 TO 30KTS SHOULD DECREASE TO 8 TO 13KTS AFTER 00Z. SOUTH TO
SOUTHWEST SURFACE WINDS WILL INCREASE AGAIN FOR AT 12 TO 16KTS
SUSTAINED AND GUSTS 18 TO 25KTS AFTER 14Z TUESDAY. DID MENTION LOW
LEVEL WIND SHEAR AT ALL THREE SITES STARTING BETWEEN 04Z AND 06Z AT
KOMA AND KLNK AND BETWEEN 06Z-08Z AT KOFK INTO TUESDAY MORNING.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$