Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 260553
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1253 AM CDT SUN JUL 26 2015

.DISCUSSION...
ISSUED AT 456 PM CDT SAT JUL 25 2015

UPDATE...HAVE ADDED MONTGOMERY AND PAGE COUNTIES IN IOWA TO HEAT
ADVISORY HEADLINE.

MAIN FORECAST CONCERNS ARE OVERNIGHT CONVECTION AND HEAT INDEX
VALUES ON SUNDAY.

TONIGHT...LINGERING AFTERNOON CONVECTION ALONG WITH NEW
DEVELOPMENT OF THUNDERSTORMS WILL BE THE PRIMARY CONCERN. THERE
WILL BE TWO AREAS TO WATCH...NORTHEAST NEBRASKA AND SOUTHEAST
NEBRASKA/SOUTHWEST IOWA. NEW CONVECTION IS EXPECTED TO DEVELOP IN
CENTRAL SOUTH DAKOTA AND MOVE INTO NORTHEAST NEBRASKA THIS
EVENING. OVERALL SEVERE PARAMETERS SUGGEST THE NORTHERN AREA WILL
BE AT A HIGHER RISK FOR SEVERE WEATHER WHILE TO THE SOUTH HEAVY
RAINFALL IS THE BIGGER THREAT. IN THE NORTH MID-LAYER SHEAR WILL
BE ON THE INCREASE ALLOWING FOR BETTER STORM ORGANIZATION.

ACROSS THE NEBRASKA/KANSAS BORDER SOME STORMS COULD PRODUCE
LOCALLY HEAVY RAINFALL. THIS EVENING DEEP LAYER MOISTURE IS MORE
THAN SUFFICIENT TO CAUSE LOCALIZED FLASH FLOODING. THE WIDESPREAD
THREAT THOUGH IS LOW GIVEN THE TIME OF YEAR IN THE GROWING SEASON
AND THAT ANTECEDENT CONDITIONS ARE WET BUT NOT TO THE POINT OF
NEEDING A FLASH FLOOD WATCH. THIS THREAT WILL BE HANDLED ON A
STORM BY STORM BASIS AND WARNINGS WILL BE ISSUED AS NEEDED.

SUNDAY...OPTED TO ISSUE A HEAT ADVISORY FOR SUNDAY FOR MUCH OF
SOUTHEAST NEBRASKA AND A FEW COUNTIES IN SOUTHWEST IOWA. HEAT
INDEX VALUES SHOULD EASILY REACH 105 DEGREES BY LATE AFTERNOON
ACROSS SOUTHEAST NEBRASKA. OPTED TO ALSO INCLUDE THE OMAHA/COUNCIL
BLUFFS METRO...EVEN THOUGH AREAS AWAY FROM THE URBAN ENVIRONMENT
MAY NOT SEE HEAT INDEX VALUES MUCH ABOVE 100 DEGREES. HEAT ASIDE
EXPECT DRY WEATHER AS THE REGION IS IN BETWEEN WEATHER SYSTEMS.

SUNDAY NIGHT THROUGH NEXT SATURDAY...THE WEATHER DURING THIS
PERIOD WILL BE DOMINATED BY AN UPPER LEVEL LOW PRESSURE SYSTEM
MOVING FROM THE PACIFIC NORTHWEST ON MONDAY TO HUDSON BAY ON
THURSDAY. AHEAD OF THIS SYSTEM ON SUNDAY NIGHT A WEAK MID LEVEL
SHORTWAVE WILL MOVE THROUGH. THIS FEATURE SHOULD SPARK OFF SOME
SHOWERS AND THUNDERSTORMS GIVEN THE AMPLE MOISTURE IN PLACE. THEN
MONDAY NIGHT THROUGH TUESDAY THE UPPER LEVEL SYSTEM WILL DRAG A
COLD FRONT THROUGH THE AREA. MOISTURE LOOKS TO POOL AHEAD OF THE
FRONT AS PRECIPITABLE WATER VALUES EXCEED 2 INCHES BY TUESDAY
AFTERNOON. THIS WILL PRESENT A HEAVY RAIN POTENTIAL FOR THE AREA
FOR TUESDAY NIGHT AND INTO EARLY WEDNESDAY MORNING. THE FRONT
SHOULD BE WELL CLEAR OF THE AREA BY WEDNESDAY AFTERNOON.
THEREAFTER 500MB HEIGHTS ARE ON THE RISE AND MUCH QUIETER WEATHER
PATTERN SETTLES IN UNDER A STRENGTHENING WESTERN CONUS RIDGE. A
FEW WEAK SHORTWAVES MAY SNEAK THROUGH DURING THIS TIME BUT TIMING
AND MOISTURE ARE HARD TO PIN DOWN. OVERALL TEMPERATURES ARE NOT
TOO BAD WITH DAYTIME HIGHS IN THE UPPER 80S.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1248 AM CDT SUN JUL 26 2015

THERE IS SOME THREAT OF AN ISO SHRA OVERNIGHT IN ASSOCIATED WITH
THE LOW LEVEL JET. THIS APPEARS MOST LIKELY AT KOMA...BUT WILL
LEAVE THE TAFS DRY ATTM UNTIL WE START TO SEE SOME DEVELOPMENT.
OTHERWISE WE SHOULD SEE A GOOD DEAL OF MID-LEVEL CLOUDS AT ALL THE
TAF SITES OVERNIGHT. WE MAY SEE SOME MVFR VISBY OCCUR TOWARD MRNG
AT ESPECIALLY KOFK. VFR CONDS AND DRY WEATHER IS EXPECTED ON SUN
WITH A FEW CU AND SOUTHEAST WINDS.

&&


.OAX WATCHES/WARNINGS/ADVISORIES...
NE...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
     FOR NEZ052-053-065>068-078-088>093.

IA...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
     FOR IAZ069-079-080-090-091.

&&

$$

DISCUSSION...PEARSON
AVIATION...BOUSTEAD



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