FXUS63 KOAX 210853
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
353 AM CDT THU APR 21 2011
.DISCUSSION...
FORECAST CONCERNS THROUGH THE PERIOD WILL BE PLACEMENT AND TIMING
OF SHOWERS AND THUNDERSTORMS ALONG WITH TEMPERATURES.
AT 08Z...SURFACE HIGH PRESSURE WAS CENTERED OVER IOWA AND
ILLINOIS...WITH SOUTHEAST FLOW AND TEMPERATURES IN THE 30S AND 40S
ACROSS THE FORECAST AREA. THE LATEST RADAR MOSAIC HAD ONE AREA OF
PRECIPITATION OVER WEST CENTRAL AND CENTRAL NEBRASKA WITH
ADDITIONAL SHOWERS AND THUNDERSTORMS FROM WYOMING INTO COLORADO
AND UTAH.
ALTHOUGH THE MAIN SHORTWAVE TROUGH IS STILL OVER THE WEST
COAST...THERE ARE A COUPLE OF WAVES EMBEDDED IN THE SOUTHWEST
FLOW AHEAD OF IT. THE FIRST PIECE OF ENERGY WILL MOVE ACROSS THE
FORECAST AREA THIS MORNING. SHOWERS ARE MORE LIKELY OVER THE
NORTHERN HALF OF THE FORECAST AREA. THERE IS SOME DRY AIR IN PLACE
AND THIS WILL WORK AGAINST THE PRECIPITATION...HOWEVER WITH STRONG
H700MB WARM AIR ADVECTION THRU 18Z...WILL COUNT ON IT MOISTENING FROM
THE TOP DOWN...ESPECIALLY ALONG AND NORTH OF I80. RAINFALL AMOUNTS
WILL BE ON THE LIGHT SIDE AS THE PRECIP MOVES THROUGH FAIRLY
QUICK. SOUTHEAST SURFACE WINDS INCREASE THIS AFTERNOON...
MEANWHILE...STRENGTHENING H85 FLOW WILL RETURN DEEPER MOISTURE
INTO THE AREA WITH SHOWERS AND THUNDERSTORMS ESPECIALLY FROM
SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA. TONIGHT INTO FRIDAY MID
TROPOSPHERIC LOW PRESSURE DEEPENS OVER SOUTH DAKOTA. THERE IS A
PRIMARY AREA OF SURFACE LOW PRESSURE OVER SOUTH DAKOTA WITH A
SECONDARY SURFACE LOW PRES SYSTEM OVER NORTHWEST MISSOURI. THE
FORECAST AREA WILL BE IN BETWEEN THE LOW CENTERS WITH THE MORE
ORGANIZED PRECIP TO THE SOUTH AND SOUTHOF THE FORECAST AREA. FOR
NOW WILL INCLUDE SOME SCATTERED SHOWERS...AND A BETTER CHANCE FOR
THUNDERSTORMS IN SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. FRIDAY
AFTERNOON LOOKS TO DRY OUT CONSIDERABLY AND THIS SHOULD HELP BOOST
TEMPERATURES INTO THE 60S. FRIDAY NIGHT INTO SATURDAY LOOKS MAINLY
DRY. COULD SEE SOME ISOLATED SHOWERS DEVELOP SATURDAY AFTERNOON IN
THE SOUTH WITH AFTERNOON HEATING.
THE FORECAST REMAINS UNSETTLED INTO SUNDAY AND EARLY NEXT WEEK. SUNDAY
THERE STILL IS A CHANCE OF PRECIP IN THE SOUTH...DEPENDING ON
WHERE THE SURFACE BOUNDARY INTO KANSAS AND MISSOURI. THERE IS A
STORM SYSTEM MONDAY INTO TUESDAY THAT WRAPS UP OVER THE PLAINS AND
BRINGS SOME SHOWERS AND THUNDERSTORMS TO THE REGION.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS WITH MID LEVEL CIGS WILL BEGIN THE PERIOD...BUT
DETERIORATING CONDITIONS ARE EXPECTED THROUGH THURSDAY. SHOWERS AND
ISOLATED THUNDERSTORMS WILL MOVE NORTHEAST FROM WESTERN NEBRASKA AND
WILL LIKELY WORK INTO KOFK AREA BETWEEN 12Z AND 18Z. ATTENDANT MVFR
CIGS/VSBYS ARE POSSIBLE THEN. KOMA AND KLNK WILL SEE LOWERING CIGS
TO FL040-060 DURING THIS TIME WITH ONLY ISOLATED SHOWERS. SHOWERS
SHOULD MOVE OFF TO THE EAST BY 18Z...THEN LOW LEVEL SOUTHEAST FLOW
WILL BRING MOISTURE NORTH AGAIN BEFORE 00Z. MORE SHOWERS AND
THUNDERSTORMS ARE POSSIBLE...ESPECIALLY IN KLNK AND KOMA AREAS...BUT
MAIN AVIATION CONCERN WILL BE LOWERING CIGS TO IFR. THOSE IFR CIGS
WILL PERSIST THROUGH FRIDAY MORNING WITH OFF AND ON SHRA/TSRA
CHANCES.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY/DERGAN