000
FXUS63 KOAX 181715
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1215 PM CDT TUE JUN 18 2013

.AVIATION...

18Z TAFS FOR KOMA...KLNK...KOFK.

PCPN CONTINUED TO DECREASE IN COVERAGE AS OF JUST AFTER NOON NEAR
THE TAF SITES. EXPECT THAT CLOUDS WILL DECREASE THROUGH THE AFTN.
VFR CONDITIONS SHOULD PREVAIL UNTIL LATE TONIGHT WHEN SOME 4-6
MILE VSBY RESTRICTIONS WILL BE POSSIBLE.

MILLER

&&

.PREV DISCUSSION... /ISSUED 942 AM CDT TUE JUN 18 2013/

UPDATE...

SHRA AND TSRA WILL PROBABLY LINGER OVER PARTS OF THE AREA INTO AT
LEAST EARLY AFTN AND POSSIBLY MID AFTN. THIS IS BEING AIDED BY A
WEAK SHORTWAVE TROUGH AND UPPER LEVEL DIVERGENCE ASSOCIATED WITH
THE RIGHT ENTRANCE REGION OF AN 80 KNOT JET STREAK AT 300 MB OVER
CENTRAL IOWA. ACTIVITY SHOULD SHIFT DOWN TO MAINLY ALONG THE KS
AND MO BORDERS BY 19Z OR 21Z. MADE SOME ADJUSTMENTS FOR SKY
CONDITION AND HOURLY TEMPS AS WELL. ZFP AND GRIDS ALREADY UPDATED.

MILLER

PREV DISCUSSION...  /ISSUED 341 AM CDT TUE JUN 18 2013/

DISCUSSION...

WATER VAPOR IMAGERY AND UPPER AIR ANALYSIS SHOW A CLOSED LOW JUST
OFF THE PACIFIC NORTHWEST COAST WITH A RIDGE OF HIGH PRESSURE
EXTENDING FROM NORTHERN MEXICO NORTH THROUGH CENTRAL COLORADO AND
INTO WESTERN ALBERTA. A WEAK SHORTWAVE WAS NOTED NEAR THE FOUR
CORNERS REGION WHILE ANOTHER SHORTWAVE TROUGH WAS MOVING SOUTHEAST
ACROSS THE EASTERN DAKOTAS ON THE BACKSIDE OF THE RIDGE. AT THE
SURFACE...A BROAD AREA OF HIGH PRESSURE EXTENDED SOUTH FROM THE
CANADIAN PRAIRIE PROVINCES INTO THE CENTRAL PLAINS.

WEAK AND ISOLATED TSTMS HAVE DEVELOPED ACROSS THE FORECAST AREA IN
ASSOCIATION WITH THE ENHANCED LIFT FROM THE EASTERN DAKOTAS
SHORTWAVE TROUGH. DO NOT ANTICIPATE THIS ACTIVITY TO LAST MUCH
PAST THE MORNING AS THE LIFT FROM THE WAVE EXITS THE AREA. WITH
THAT SAID...EXPECTING DRY CONDITIONS FOR MUCH OF THE DAY WHILE
THE PACIFIC NORTHWEST LOW MOVES ONSHORE AS THE RIDGE BUILDS OVER
OUR AREA. THE ABOVE MENTIONED SHORTWAVE TROUGH CURRENTLY NEAR THE
FOUR CORNERS REGION IS PROGGED TO ADVANCE INTO THE HIGH PLAINS
REGION THIS EVENING AND SET OFF A ROUND OF THUNDERSTORMS IN
UPSLOPE FLOW OVER THE HIGH PLAINS. THESE MAY SPREAD EAST INTO THE
FORECAST AREA OVERNIGHT AS THE UPPER SHORTWAVE CONTINUES EAST. IT
REMAINS QUESTIONABLE AS TO HOW FAR EAST THEY WILL SPREAD
OVERNIGHT/EARLY MORNING GIVEN THE STABLE AIRMASS THEY WILL BE
MOVING INTO. IN ANY CASE...THUNDERSTORM CHANCES RETURN WEDNESDAY
AFTERNOON AS THUNDERSTORMS DEVELOP TO OUR WEST. STRONG ISENTROPIC
LIFT IN WARM AIR ADVECTION REGIME WILL WARRANT POPS BY LATE
AFTERNOON AS TSTMS SPREAD EAST INTO THE AREA.

THE UPPER RIDGE WILL CONTINUE TO BUILD OVER THE AREA THROUGH THE
END OF THE WEEK AS TROUGHING OCCURS IN THE WEST. 850 MB TEMPS ARE
FORECAST TO RISE INTO THE UPPER 20`S C WHICH SHOULD PUSH HIGHS
INTO THE 90S FOR THE END OF THE WEEK. THE CWA WILL REMAIN IN THE
WARM SECTOR AS THE SFC FRONT REMAINS TO OUR NORTH. VERY WARM MID
LEVELS SHOULD INHIBIT ANY CONVECTION FROM DEVELOPING/SPREADING
INTO THE CWA AND SO HAVE LEFT THE EARLY PORTION OF THE WEEKEND
DRY. THE FRONT SAGS SOUTH EARLY SUNDAY AND SO THUNDERSTORM CHANCES
WILL RETURN FOR THE END OF THE WEEKEND.

KERN

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$