Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 172017
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
317 PM CDT THU JUL 17 2014

.SHORT TERM...(TONIGHT THROUGH SUNDAY)
ISSUED AT 310 PM CDT THU JUL 17 2014

WARMER AND MORE HUMID CONDITIONS WITH SMALL RAIN CHANCES ARE THE
PRIMARY FORECAST CONCERNS.

UPPER SHORTWAVE FROM WISCONSIN INTO KANSAS WAS CAUSING SCATTERED
CONVECTION ACROSS KANSAS AND OKLAHOMA TODAY...AND PRODUCING VARIABLE
CLOUD COVER ACROSS EASTERN NEBRASKA AND WESTERN IOWA. THIS WAVE WILL
CONTINUE DRIFTING SOUTHEAST TONIGHT...LEAVING THE MIDDLE OF THE
COUNTRY UNDER NORTHWEST FLOW ALOFT INTO SATURDAY. BY SUNDAY...UPPER
RIDGING WILL BEGIN NOSING INTO THE REGION FROM THE SOUTH AND
SOUTHWEST.

AT THE SURFACE...HIGH PRESSURE WAS MOVING OFF TO THE EAST
TODAY...BRINGING SOUTH AND SOUTHEAST WINDS TO OUR AREA. GIVEN
NORTHWEST FLOW ALOFT...SURFACE TROUGH IS FORECAST TO SET UP IN THE
HIGH PLAINS ON FRIDAY AND REMAIN IN PLACE THROUGH THE WEEKEND. SO
THIS COMBINATION OF SLOWLY RISING HEIGHTS ALOFT AND SOUTHERLY LOW
LEVEL FLOW SUGGESTS WARMER AND MORE HUMID CONDITIONS WILL PREVAIL
OVER THE WEEKEND. EXPECT HIGHS TO GAIN A CATEGORY EACH
DAY...AVERAGING NEAR 80 FRIDAY...LOW TO MID 80S SATURDAY...AND MID
TO UPPER 80S SUNDAY. SIMILAR INCREASE FOR LOWS RANGING FROM NEAR
60 FRIDAY MORNING TO THE MID AND UPPER 60S BY SUNDAY MORNING.

PRECIPITATION CHANCES STILL LOOK RELATIVELY LOW THROUGH SUNDAY. AXIS
OF HIGHEST INSTABILITY IS FORECAST TO REMAIN WEST OF OUR AREA
THROUGH SATURDAY...FAVORING WESTERN AND CENTRAL NEBRASKA INTO SOUTH
DAKOTA. HOWEVER THAT AXIS BENDS EAST INTO NORTHEAST NEBRASKA
SATURDAY NIGHT AS PER GFS 850 LIFTED INDEX PROGS...COINCIDING WITH
45KT LOW LEVEL JET AND STRONG THETA-E ADVECTION. EXPECT ELEVATED
CONVECTION TO FIRE IN THIS REGIME AFTER MIDNIGHT SATURDAY NIGHT AND
COULD LINGER INTO THE EARLY DAYLIGHT HOURS SUNDAY. BEYOND
THEN...WARMING MID LEVEL TEMPERATURES UNDER BUILDING RIDGE SHOULD
CAP CHANCES FOR ANY AFTERNOON CONVECTION.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM CDT THU JUL 17 2014

WARMER AND MORE HUMID CONDITIONS WILL DOMINATE THE LONGER TERM
PERIOD AS WELL...WITH ONLY SMALL OFF-AND-ON PRECIPITATION CHANCES.
UPPER RIDGE WILL CONTINUE TO BUILD INTO THE PLAINS WITH PERSISTENT
SOUTHERLY LOW LEVEL FLOW. THIS PATTERN SUGGESTS A GAIN OF A COUPLE
OF DEGREES EACH DAY FOR HIGHS AND LOWS...WITH 90S THE RULE MONDAY
THROUGH THURSDAY. SURFACE DEW POINT TEMPERATURES SHOULD REACH THE
70S FOR A GOOD PART OF THE LONG TERM...AND COMBINED WITH AFTERNOON
HIGHS...EXPECT HEAT INDICES TO AVERAGE 100 TO 105 EACH AFTERNOON.

RAIN CHANCES SHOULD CONTINUE TO FAVOR OVERNIGHT HOURS AS WARM MID
LEVEL TEMPERATURES INHIBIT AFTERNOON CONVECTION. THE POTENTIAL FOR
WEAK SHORTWAVES RIDING THROUGH MEAN RIDGE POSITION WILL ENHANCE
THESE CHANCES...BUT TIMING THESE THIS FAR OUT IS EXTREMELY DIFFICULT
AT BEST. BOTH GFS AND ECMWF SUGGEST MONDAY NIGHT AND TUESDAY NIGHT
OFFER THE BEST CHANCE FOR CONVECTION...SO WILL CONTINUE OUR SMALL
CHANCES FOR THUNDERSTORMS THEN.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 110 PM CDT THU JUL 17 2014

VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THE PERIOD WITH
SCT-BKN LAYER OF CU THROUGH ABOUT 00Z. A PERIOD OF MVFR VSBY IS
POSSIBLE 10Z-14Z AS LIGHT TO CALM WINDS AGAIN DEVELOP DURING THE
OVERNIGHT PERIOD.

&&

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

$$

SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...FOBERT



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