FXUS63 KOAX 180818
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
318 AM CDT MON JUL 18 2011
.DISCUSSION...
HEAT THROUGH MID WEEK...THEN INTRODUCING A CHANCE FOR THUNDERSTORMS
AFTER THAT...ARE THE PRIMARY FORECAST CONCERNS.
BROAD UPPER RIDGE/HIGH WAS ENTRENCHED OVER THE MIDDLE OF THE COUNTRY
THIS MORNING...AND MODELS KEEP IT IN PLACE THROUGH WEDNESDAY. THIS
GOES ALONG NICELY WITH OUR CURRENT EXCESSIVE HEAT WARNING...SO NO
CHANGES WILL BE TO THAT WITH THIS PACKAGE. THE ONLY REAL CHANGE
THROUGH WEDNESDAY FROM PREVIOUS MODEL RUNS IS A TREND TOWARD MORE
SOUTHWESTERLY 850 FLOW THAT WILL BE MIXED DOWN DURING THE AFTERNOON
TODAY THROUGH WEDNESDAY. WHERE SOUTHWEST LOW LEVEL FLOW DEVELOPS...
TEMPERATURES WILL BE PUSHED UPWARD AND DEW POINTS DOWNWARD. SO WE
WILL LIKELY SEE MORE 100+ DEGREE READINGS THAN PREVIOUS FORECAST
SUGGESTED...AND MORE DEW POINTS DROPPING INTO THE 60S. AND SOME
AFTERNOON HEAT INDICES MAY HOLD NEAR OR JUST BELOW 105. BUT THE
PROLONGED HEAT WAVE THAT IS ALREADY A FEW DAYS OLD WILL PERSIST.
A SLIGHT BREAKDOWN IN THE RIDGE WEDNESDAY NIGHT OVER OUR AREA LOOKS
MORE EVIDENT ON 00Z RUNS OF NAM/GFS/ECMWF. ALL THESE MODELS PUSH A
WEAK COLD FRONT/WIND SHIFT INTO NEBRASKA WEDNESDAY NIGHT...AND
DEVELOP CONVECTION WHERE 700MB TEMPERATURES COOL INTO THE LOWER
TEENS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. AM NOT TOTALLY
CONVINCED STORM TRACK WILL SETTLE THIS FAR SOUTH...BUT AM NOT GOING
TO ARGUE WITH INTER-MODEL CONSISTENCY AT THIS POINT. SO WILL
INTRODUCE SMALL PRECIPITATION CHANCES WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. IF THE RIDGE BREAKDOWN DOES OCCUR AS MODELS
SUGGEST...WE MAY SEE OFF AND ON RAIN CHANCES RIGHT THROUGH THE
WEEKEND AS PER ECMWF.
WILL TRIM TEMPERATURE A TAD WITH INCREASED RAIN CHANCES AND CLOUDS
THURSDAY. BUT STILL AVERAGING AT OR ABOVE NORMAL FOR ALL OF OUR
AREA.
DERGAN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS WILL PREVAIL AT ALL THREE TAF SITES THROUGH THE
FORECAST PERIOD AS THE UPPER LEVEL RIDGE REMAINS IN PLACE. IT WILL
REMAIN HOT AND HUMID THROUGH THE PERIOD AS WELL.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT WEDNESDAY FOR NEZ011-012-
015>018-030>034-042>045-050>053-065>068-078-088>093.
IA...EXCESSIVE HEAT WARNING UNTIL 7 PM CDT WEDNESDAY FOR IAZ043-055-
056-069-079-080-090-091.
&&
$$