Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 311043
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
543 AM CDT FRI JUL 31 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM CDT FRI JUL 31 2015

DEWPOINTS HAVE CLIMBED BACK INTO THE MID TO UPPER 60S ACROSS THE
LOCAL OVER OVER THE PAST 24 HOURS AS SOUTHERLY RETURN FLOW HAS
HELPED STEER LOW LEVEL MOISTURE BACK ACROSS THE REGION. THIS
INCREASE MOISTURE WILL HELP INSTABILITY BUILD BACK ACROSS THE LOCAL
ARE BY EARLY AFTERNOON...WHICH COMBINED WITH MODEST SHEAR
VALUES...JUSTIFIES THE MENTION OF SOME STRONG TO MARGINALLY SEVERE
SHOWERS AND THUNDERSTORMS DURING THE LATE AFTERNOON AND EARLY
EVENING HOURS.

WHILE THERE WILL BE AMPLE INSTABILITY AND LITTLE INHIBITION FOR
STORM FORMATION...THE LACK OF ANY SIGNIFICANT FORCING MECHANISM IN
NORTHWESTERLY FLOW ALOFT WILL LIKELY RESULT IN ANY ACTIVITY BEING
PRIMARILY DIURNALLY DRIVEN ACROSS THE LOCAL AREA LATER TODAY. IN
ADDITION...THERE WILL CONTINUE TO BE A WEAK FRONTAL BOUNDARY IN
THE VICINITY OF THE LOCAL AREA...WHICH COULD VERY WELL BECOME THE
FOCUS FOR CONVECTIVE DEVELOPMENT THIS AFTERNOON. GIVEN THIS...IT
IS NOT SURPRISING THAT THE LOCAL AREA REMAINS IN MARGINAL RISK FOR
SEVERE WEATHER FROM SPC FOR LATER TODAY. IN GENERAL...MODEL DATA
IS NOT IN GREAT AGREEMENT WITH THUNDERSTORM COVERAGE THIS
AFTERNOON...BUT MOST MODELS DO INDICATE SOME CONVECTIVE
DEVELOPMENT ACROSS THE LOCAL AREA...WITH THE 00Z WRF BEING THE
MOST AGGRESSIVE. SO WITH CONSENSUS THAT AT LEAST SOME STORMS WILL
FORM...BUMPED UP PROBABILITIES BY ROUGHLY 10 PERCENT FOR MOST
AREAS LATER TODAY.

OTHERWISE...EXPECT A SEASONAL AFTERNOON ACROSS THE REGION WITH HIGH
TEMPERATURES TOPPING OUT NEAR 90 DEGREES...AND OVERNIGHT LOW
TEMPERATURES DROPPING BACK INTO THE MIDDLE TO UPPER 60S. AS
PREVIOUSLY MENTIONED...WITH THIS AFTERNOONS ACTIVITY EXPECTED TO BE
PRIMARILY DIURNALLY DRIVEN...EXPECT ANY ACTIVITY THAT DOES DEVELOP
TO DIMINISH FAIRLY RAPIDLY AFTER SUNSET TONIGHT...WITH MOSTLY DRY
CONDITIONS EXPECTED TO RETURN DURING THE OVERNIGHT HOURS.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 418 AM CDT FRI JUL 31 2015

OVERALL...NO "MAJOR" CHANGES WERE MADE TO THIS 6-DAY PERIOD VERSUS
PREVIOUS FORECAST...AS ALL IN ALL IT`S A PRETTY TYPICAL SUMMER
WEATHER PATTERN WITH TEMPERATURES LOOKING TO PREVAIL AT NEAR-TO-
SLIGHTLY ABOVE NORMAL VALUES...AND VARIOUS HIGHLY-UNCERTAIN
CHANCES FOR SHOWERS/STORMS SPRINKLED THROUGHOUT. BY SUMMER
STANDARDS THOUGH...THERE IS PROBABLY A BIT MORE UNCERTAINTY THAN
USUAL IN TEMPERATURES FOR THE DAY 6-7 TIME FRAME NEXT WEDNESDAY-
THURSDAY (SEE BELOW FOR MORE).

WILL START BY TAKING A BROAD OVERVIEW OF BOTH PRECIPITATION/SEVERE
WEATHER AND TEMPERATURE TRENDS...

RAIN AND THUNDERSTORM CHANCES/SEVERE WEATHER POTENTIAL INCLUDING
SATURDAY: OF THESE 11 DAY/NIGHT FORECAST PERIODS (TWELVE HOUR
BLOCKS)...ONLY 2 CONTINUE TO CARRY A COMPLETELY "DRY" FORECAST
CWA-WIDE...THOSE BEING SUNDAY-SUNDAY NIGHT. NOT SURPRISINGLY
THOUGH...EVEN THIS TIME FRAME IS NO "GUARANTEE" TO REMAIN
COMPLETELY VOID OF CONVECTION AS A FEW MODELS PAINT
LIMITED/ISOLATED POTENTIAL WITHIN PARTS OF THE AREA...BUT NOTHING
YET WORTHY OF ADVERTISING 15+ PERCENT MENTIONABLE CHANCES (POPS)
YET. OF THE OTHER 9 PERIODS THAT DO ADVERTISE PRECIP CHANCES
WITHIN AT LEAST SOME PORTION OF THE CWA...THE VAST MAJORITY OF
THEM ARE ONLY IN THE 20-30 PERCENT RANGE DUE TO TYPICAL ABOVE-
AVERAGE UNCERTAINTY IN A PREVALENT WEST-NORTHWEST FLOW SUMMER
PATTERN. ALTHOUGH FAR FROM TAKING TO THE BANK...AT LEAST AT THIS
POINT THE OVERALL "BEST" WINDOWS OF OPPORTUNITY FOR POTENTIALLY
(KEY WORD POTENTIALLY) MORE WIDESPREAD RAINFALL POTENTIAL ACROSS
THE AREA MIGHT BE LATE SATURDAY AFTERNOON/EVENING (ESPECIALLY
WITHIN THE NORTHEAST CWA)...THEN THE TUESDAY-TUESDAY NIGHT TIME
FRAME AS A POTENTIALLY SEMI-ORGANIZED LOW PRESSURE SYSTEM MOVES
THROUGH THE REGION...AND THEN POSSIBLY AGAIN AROUND WEDNESDAY
NIGHT...ALTHOUGH OF COURSE THIS IS REALLY FAR OUT THERE TO GET TOO
EXCITED ABOUT. AS FOR SEVERE WEATHER CHANCES...IT APPEARS THAT
THIS 6-DAY PERIOD WILL PROBABLY CONTAIN AT LEAST A FEW
OPPORTUNITIES...AS TYPICALLY DECENT SUMMER INSTABILITY VALUES
COMBINE WITH WHAT APPEARS TO BE A SOMEWHAT ABOVE-AVERAGE REGIME OF
DEEP LAYER WIND SHEAR VALUES (THANKS TO STRONGER FLOW ALOFT). OF
COURSE...GIVEN THAT FORCING ALOFT IS GENERALLY FAIRLY WEAK...THE
SPECIFICS OF SEVERE WEATHER POTENTIAL ON MOST DAYS/NIGHTS IS STILL
VERY MUCH OUT OF REACH...AND AGREE WITH THE LATEST SPC DAY 4-8
OUTLOOK IN KEEPING THE MONDAY-THURSDAY TIME FRAME IN
"PREDICTABILITY TOO LOW" TERRITORY. HOWEVER...IN THE NEARER-
TERM...SATURDAY/SATURDAY EVENING IS LOOKING AT LEAST SOMEWHAT
INTRIGUING FOR MAINLY THE NORTHEAST 1/2 OF THE CWA...AS THE LATEST
SPC DAY 2 OUTLOOK GOES WITH A MARGINAL RISK FOR MUCH OF THAT
AREA...BUT WHILE KEEPING THE VAST MAJORITY OF THE CWA JUST WEST OF
THE LARGER SLIGHT RISK AREA CENTERED OVER IA. WHILE MODELS VARY
CONSIDERABLY ON THE AREAL COVERAGE AND SPECIFIC LOCATION OF
CONVECTION...THE MOST STRIKING FEATURE HERE IS SOMEWHAT STRONGER-
THAN-AVERAGE DEEP LAYER WIND SHEAR FOR MID-SUMMER...WITH 0-6KM
SHEAR LOOKING TO AVERAGE SOLIDLY INTO THE 35-40KT RANGE. WHILE
AREAS SLIGHTLY EAST-NORTHEAST OF THE CWA MAY BE MORE FAVORED TO
SEE MORE WIDESPREAD COVERAGE OF A SEVERE THREAT...VARIOUS MODELS
SUCH AS THE NAM/GFS/ECMWF AND THE HIGHER-RESOLUTION SIMULATED
REFLECTIVITY FROM THE 4KM WRF-ARW ALL PAINT "SOME" CONVECTIVE
POTENTIAL WITHIN MAINLY THE NORTHEAST 1/2 OF THE CWA. SHOULD
SEVERE CONVECTION IN FACT MATERIALIZE SATURDAY
AFTERNOON/EVENING...WE COULD BE DEALING WITH A FEW RATHER
INTENSE...FAIRLY DISCRETE SOUTHEAST-MOVING SUPERCELLS...OR
POSSIBLY A LARGER CLUSTER OF STORMS. EITHER WAY...A DECENT
HAIL/WIND THREAT COULD EXIST...AND THIS TIME FRAME BEARS WATCHING
DESPITE CURRENTLY "ONLY" BEING CARRYING AN SPC MARGINAL RISK FOR
MOST OF THE LOCAL AREA OF CONCERN.

TEMPERATURES: PER THE LATEST OFFICIAL FORECAST...THIS IS OVERALL A
NEAR-TO-ABOVE NORMAL TEMPERATURE REGIME THROUGH THESE 6
DAYS...WITH HIGHS ACROSS MOST OF THE CWA REACHING LOW-MID 90S
TERRITORY FROM SATURDAY-MONDAY...BEFORE A "SLIGHT" COOL-DOWN MORE
SO INTO THE MID-80S TO LOW-90S FROM TUESDAY-THURSDAY.
HOWEVER...THE ECMWF/GFS MODEL SOLUTIONS HAVE BEEN STRUGGLING A BIT
WITH THESE LATTER 3 DAYS LATELY...AND ITS WORTH NOTING THAT THESE
VERY LATEST 00Z RUNS OF BOTH MODELS ARE NOW IN BETTER AGREEMENT
THAT THERE MIGHT NOT BE MUCH OF A COOL-DOWN AT ALL...AND IF THESE
TRENDS HOLD...DO NOT BE SURPRISED IF MID-LATE WEEK HIGHS START TO
INCREASE IN LATER FORECASTS. OF COURSE...A FEW DAYS MAY BE PRONE
TO COOLING EFFECTS OF CONVECTION/CLOUD COVER IN SOME AREAS...BUT
THIS IS IMPOSSIBLE TO RESOLVE IN ADVANCE. AT LEAST FOR NOW...NO
DAYS APPEAR TO CARRY A THREAT OF WIDESPREAD HEAT INDEX VALUES OF
100+ DEGREES. NIGHTLY LOW TEMPERATURES TEND TO CARRY A BIT HIGHER
DEGREE OF CONFIDENCE THIS TIME OF YEAR...AND MOST NIGHTS LOOK TO
FEATURE TYPICAL VALUES IN THE MID-60S TO NEAR 70 RANGE...CERTAINLY
NOTHING THAT RESEMBLES THE MORE FALL-LIKE READINGS ON A FEW RECENT
MORNINGS.

FINISHING UP WITH A FAIRLY QUICK LOOK AT THE LARGER-SCALE PATTERN
EXPECTATIONS AND VARIOUS UNCERTAINTIES IN 1-2 DAY CHUNKS:

SATURDAY DAYTIME-NIGHT: SEE THE MAIN PRECIP/SEVERE WEATHER
PARAGRAPH ABOVE FOR MORE DETAILS ON THE INGREDIENTS THAT "MIGHT"
COME TOGETHER TO BRING A SEVERE WEATHER THREAT TO MAINLY THE
NORTHEAST 1/2 OF THE CWA. IN THE MID-UPPER LEVELS...SEASONABLY
STRONG NORTHWEST-FLOW WILL BE OVERHEAD AS THE REGION IN THE
INTERFACE OF STRONGER FLOW BETWEEN SUBTROPICAL RIDGE OVER THE
SOUTHWEST CONUS AND THE MAIN CORE OF STRONGER FLOW CENTERED OVER
THE NORTH CENTRAL/NORTHEAST CONUS. WHILE LARGE-SCALE FORCING IS
RELATIVELY NEBULOUS AND LIKELY TIED TO ONLY A FAIRLY WEAK...LOW
AMPLITUDE SHORTWAVE TROUGH...THE THREAT FOR STORMS IS SOMEWHAT
CONDITIONAL BUT SEEMS TO BE GAINING MODEL SUPPORT. HAVE SLIGHT
CHANCES GOING RIGHT AWAY IN THE MORNING IN NORTHEAST
COUNTIES...BUT THE BETTER CHANCES AND PRIMARY POSSIBLE SEVERE RISK
ARRIVES FOR THE LATE AFTERNOON/EVENING AND HAVE SOME 30 POPS HERE.
MOST MODELS ARE IN PRETTY GOOD AGREEMENT THAT THE RESPONSIBLE
DISTURBANCE SHOULD BE EXITING THE AREA BY MIDNIGHT...SO
MAINTAINED A PRECIP- FREE FORECAST FOR THE LATE NIGHT HOURS...BUT
THIS COULD BE A CLOSE CALL. NOT ACCOUNTING FOR POSSIBLE CONVECTIVE
INFLUENCES...DAYTIME BREEZES SHOULD GENERALLY AVERAGE AROUND 10
MPH FROM THE SOUTH-SOUTHWEST. HIGH TEMPS WERE NUDGED UP 1-2
DEGREES MOST AREAS.

SUNDAY DAYTIME-NIGHT: THIS 24-HOUR BLOCK REMAINS VOID OF ANY
MENTIONABLE PRECIP CHANCES...AS THE NORTHWEST FLOW ALOFT LARGELY
LACKS ANY DISCERNIBLE DISTURBANCES TO KICK THINGS OFF. NUDGED UP
HIGH TEMPS ABOUT 1 DEGREE WITH THE ENTIRE CWA INTO THE LOW-MID 90S
RANGE.

MONDAY DAYTIME-TUESDAY NIGHT: THIS 48-HOUR TIME FRAME FEATURES A
TRANSITION FROM MORE SHARP NORTHWESTERLY FLOW TO MORE OF A BROAD
WEST-NORTHWEST FLOW. BOTH THE ECMWF/GFS...THOUGH VARYING IN THE
DETAILS OF COURSE...ARE AT LEAST SHOWING HALFWAY DECENT AGREEMENT
IN PUSHING A BROAD TROUGH THROUGH THE CENTRAL PLAINS...EXTENDING
SOUTHEAST FROM THE PRIMARY DISTURBANCE OVER THE NORTHWESTERN
CONUS. ALTHOUGH THIS ENTIRE TIME FRAME CONTAINS SMALL POPS IN SOME
AREAS...THE OVERALL HIGHEST COVERAGE OF 30 POPS IS FOCUSED
TUESDAY-TUESDAY NIGHT.

WEDNESDAY DAYTIME-THURSDAY DAYTIME: AS MENTIONED EARLIER IN THE
TEMPERATURE-SPECIFIC PARAGRAPH...SOME UNCERTAINTY REMAINS
HERE...BUT THE LATEST TRENDS ARGUE FOR WARMER RATHER THAN COOLER.
IN THE MID-UPPER LEVELS...THE LOCAL REGION LOOKS TO RESIDE ON THE
VERY NORTHERN EDGE OF AN EXPANDING SOUTHERN CONUS SUBTROPICAL
RIDGE...PUTTING THE AREA IN A FAVORABLE ZONE FOR CONTINUED
THUNDERSTORM ACTIVITY...ASSUMING THAT WARMER MID LEVEL
TEMPERATURES DO NOT POSE CAPPING ISSUES.

&&

.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 540 AM CDT FRI JUL 31 2015

PREVAILING VFR CONDITIONS ARE EXPECTED AT BOTH TERMINALS THROUGH
THE PERIOD WITH LIGHT AND VARIABLE WINDS BECOMING SOUTHERLY NEAR
10KTS LATER THIS AFTERNOON. IN ADDITION...EXPECT A SMALL CHANCE
FOR A SHOWER OR THUNDERSTORM TO IMPACT THE TERMINALS DURING THE
LATE AFTERNOON OR EVENING HOURS...AND MAINTAINED A VCTS FROM
AROUND 01/00Z THROUGH 01/06Z TO COVER THIS FOR THE TIME BEING.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

SHORT TERM...ROSSI
LONG TERM...PFANNKUCH
AVIATION...ROSSI



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