FXUS63 KOAX 220813
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
311 AM CDT FRI JUL 22 2011
.DISCUSSION...
...MAIN FORECAST CHALLENGE IS POPS...
EARLY MORNING WATER VAPOR IMAGERY CONTINUES TO SHOW SUBTROPICAL
PLUME EXTENDING FROM EASTERN COLORADO INTO NEBRASKA AND IOWA. 110
KNOT WIND AT INTERNATIONAL FALLS WAS NOTED ON THE 00Z 250MB ANALYSIS
WITH 90 KNOTS AT ABERDEEN. RIGHT ENTRANCE REGION OF THIS UPPER JET
CORE WAS RESULTING IN BROAD SYNOPTIC SCALE LIFT OVER CENTRAL PLAINS
WHERE CONVECTION CONTINUES. IN THE LOWER LEVELS...THE RUC IS
SHOWING A MAXIMUM OF MOISTURE FLUX CONVERGENCE FROM 700 MB DOWN TO
THE SURFACE OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...AIDED BY A
30 KNOT SOUTHWESTERLY LOW LEVEL JET PER KOAX 88D. MODERATE TO
STRONG CAPE REMAINS IN THIS AREA AS WELL GIVEN THE LOWER TO MID 70S
DEWPOINTS.
GIVEN THE ABOVE MENTIONED FACTORS...THE PATTERN SHOULD CONTINUE TO
SUPPORT THESE SCATTERED SHOWERS AND THUNDERSTORMS THROUGHOUT MUCH OF
THE MORNING WITH A FEW POSSIBLY LINGERING INTO THE AFTERNOON OR
PERHAPS REDEVELOPING FROM THE AFTERNOON INTO THE EVENING.
SATURDAY AND SATURDAY NIGHT... MODELS ARE IN DECENT AGREEMENT
PUSHING ANOTHER COLD FRONT THROUGH THE PLAINS WITH ATTENDANT SURFACE
LOW MOVING ALONG THE NEBRASKA-SOUTH DAKOTA BORDER. THUS KEPT SMALL
POPS IN NORTHERN COUNTIES SATURDAY WITH CHANCE POPS OVER ALL OF THE
FORECAST AREA SATURDAY EVENING AS THE FRONT MOVES THROUGH THE
WARM/HUMID AIRMASS. ANY STORMS THAT DEVELOP DURING MAX HEATING
SATURDAY AFTERNOON IN THE NORTH MIGHT HAVE ENOUGH INSTABILITY AND
DEEP LAYER SHEAR TO BECOME SEVERE...WHICH IS CONSISTENT WITH THE
STORM PREDICTION CENTERS DAY 2 OUTLOOK.
THE COLD FRONT SHOULD BE THROUGH THE AREA BY 12Z SUNDAY WITH HIGH
PRESSURE BUILDING FROM THE NORTHERN PLAINS INTO NEBRASKA. FORECAST
IS DRY FROM SUNDAY INTO MID WEEK.
THE CLOUD COVER TODAY SHOULD KEEP HIGHS MAINLY IN THE LOWER 90S MOST
AREAS EXCEPT MID 90S NEAR THE KANSAS BORDER. MAXIMUM HEAT INDEX
VALUES ARE EXPECTED TO BE IN THE 100-103 RANGE...THUS BELOW HEAT
ADVISORY CRITERIA. HIGHS ON SATURDAY SHOULD BE WARMER UNLESS
SIGNIFICANT THUNDERSTORM/ANVIL PRESENCE LIMITS THE TEMPERATURES.
MOST OF THE AREA WILL STILL BE IN SOUTHERLY FLOW AHEAD OF THE FRONT
AND THE UPPER RIDGE IS EXPECTED TO BUILD BACK TO THE NORTH SATURDAY
INTO MONDAY. HIGHS SATURDAY SHOULD RANGE FROM THE MID 90S NORTH TO
100 ALONG THE KANSAS BORDER. HEAT INDICES WOULD BE CLOSER TO
ADVISORY CRITERIA ON SATURDAY IF THOSE HIGHS ARE REALIZED. WILL
HOLD OFF ON ISSUING A THIRD PERIOD ADVISORY FOR NOW GIVEN THE
UNCERTAINTY WITH THE CLOUD COVER AND HIGHS.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
MAINLY VFR CONDITIONS ARE EXPECTED AT KOFK/KOMA/KLNK. SOME ISOLATED
SHOWERS AND THUNDERSTORMS ARE POSSIBLE THROUGH 14Z AT KOMA AND
KLNK. SOME MVFR CONDITIONS CAN BE EXPECTED IN SOME OF THE SHOWERS
AND THUNDERSTORMS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
NIETFELD/SMITH