Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 080551
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
1251 AM CDT TUE JUL 8 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 349 PM CDT MON JUL 7 2014

THE BIG ISSUE FOR THE SHORT TERM WILL BE SEVERE WEATHER LATE THIS
AFTERNOON INTO THE EVENING.

DEEP LAYER SHEAR IS ABUNDANT TODAY AS AN UPPER LEVEL JET SINKS SOUTH
IN THE NORTHER TO CENTRAL PLAINS. LATEST MESOSCALE ANALYSIS INDICATES
GREATER THAN 60 KTS OF DEEP LAYER SHEAR FOR OUR
NORTH/NORTHWEST...AND 40 TO 60 KTS MOST EVERY WHERE ELSE...EXCEPT
LESS FOR SOME OF OUR NORTH CENTRAL KANSAS COUNTIES. WE HAVE QUITE A
BIT OF INSTABILITY...WITH CONVECTIVE AVAILABLE POTENTIAL ENERGY MORE
THAN 2000 J/KG FOR MOST OF OUR CWA. A HEALTHY CAP REMAINS IN
PLACE...AND PROBABLY WILL NOT BREAK UNTIL 5 OR PERHAPS 6 PM LATE
THIS AFTERNOON. THERE ARE A FEW AREAS THAT COULD FOCI FOR
CONVECTION. ONE IS A STALLED BOUNDARY REACHING INTO THE CWA NEAR THE
STATE BORDER...ANOTHER IS A LEFTOVER OUTFLOW BOUNDARY IN SOUTH
CENTRAL NEBRASKA...AND ANOTHER IS AN APPROACHING COLD FRONT DIVING
SOUTH OUT OF SOUTH DAKOTA.

THE SITUATION IS A BIT ON THE COMPLEX SIDE AT THE SURFACE...AND MY
HIGHER CHANCES OF SHOWERS AND THUNDERSTORMS IN OUR SOUTH AND EAST
MIGHT NOT HOLD WATER IF THE CONVECTION IN THE NORTH TRACKS INTO OUR
NORTHERN CWA. OUR CHANCES OF RAIN MAY NEED TO BE RAISED IN OUR
NORTH.

ISOLATED HIGH BASED STORMS HAVE ALREADY DEVELOPED OVER EASTERN
COLORADO AND NORTHWESTERN KANSAS ALONG A STALLED FRONT. WE COULD
ALSO GET SOME DEVELOPMENT FROM SOME OUTFLOW AHEAD OF THE COLD
FRONT...FROM THE CONVECTION THAT OCCURRED OVERNIGHT INTO THIS
MORNING. NUMERICAL MODELS ARE GENERALLY AGREEING THAT ONCE
CONVECTION GETS GOING...THE COLD FRONT SHOULD PICK UP THE PACE SOUTH
AGAIN...AND MUCH OUR SHOWER AND THUNDERSTORM CHANCES WILL BE PUSHED
SOUTH AND EAST BY MIDNIGHT. THE MOST LIKELY TIME FOR SHOWERS AND
THUNDERSTORMS IN THE TRI-CITIES AREA WILL BE 5 PM TO 9 PM...GIVE OR
TAKE AN HOUR OR TWO EITHER SIDE. WE COULD GET A QUICK SPIN-UP OF A
BRIEF TORNADO AS 0-1 KM HELICITY IN 50 TO 100 KTS AND LCL HEIGHTS
ARE IN THE 1250 TO 2000 RANGE. HOWEVER...GOLF BALL HAIL AND GREATER
THAN 60 MPH WILL BE THE PRIMARY THREATS.

FOR TEMPERATURES...I STUCK WITH CONSRAW FOR LOWS TONIGHT AND
BCCONSRAW FOR HIGHS TOMORROW...BASED ON GENERAL KNOWLEDGE OF MODEL
PERFORMANCE SITUATIONS INVOLVING THE TIMING OF THIS COLD FRONT.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 349 PM CDT MON JUL 7 2014

ALOFT: NW FLOW WILL DOMINATE THRU AT LEAST NEXT MON...WITH A
MODERATELY AMPLIFIED WRN USA RIDGE/ERN USA TROF. EARLY IN THIS FCST
TIME FRAME...THE HOT SUB-TROPICAL HIGH WILL BE OVER THE DESERT SW.
HOWEVER...BY FRI IT WILL EXPAND INTO THE SRN PLAINS BEFORE BEING
SQUASHED BACK INTO THE DESERT SW EARLY NEXT WEEK. ON THE WHOLE THE
LAST 3 CYCLES OF THE UKMET/GEM/EC/GFS ALL AGREE. HOWEVER...THERE IS
CONSIDERABLE CONFLICT NEXT SUN-MON IN WHAT COULD END UP A DEEP LOW
OVER ERN CANADA AND A MAJOR COOL DOWN FOR THE CNTRL/ERN USA. WILL
THE LOW DROP INTO THE NRN GREAT LAKES OR REMAIN CLOSER TO HUDSON
BAY? WE ARE PROBABLY SEEING THE EFFECTS OF TYPHOON NEOGURI WHICH
WILL BE RECURVING OVER THE W PACIFIC...AND BECOMING ABSORBED INTO
THE WESTERLIES.

ARCHAMABULT 2011 SHOWED THAT RECURVING TYPHOONS IN THE W PAC EXERT
INFLUENCE ON THE MID-LATITUDE LONGWAVES DOWNSTREAM...USUALLY LEADING
TO AMPLIFICATION AND POTENTIAL PATTERN CHANGES.

THE MOST PROMINANT SHORTWAVE TROF CONTS TO BE SLATED FOR THU.

THE EBB AND FLOW OF THE SUB-TROPICAL HIGH WILL BE DICATED BY
PERIODIC AMPLIFICATION OF THE ERN USA TROF. THIS WILL RESULT IN
ALTERNATING PERIODS OF SERIOUS SUMMER HEAT AND SPELLS OF NEAR TO
SLIGHTLY "COOLER" THAN NORMAL WX...BUT STILL VERY VERY PLEASANT FOR
SUMMMER. WE ARE ONLY TALKING THE DIFFERENCE BETWEEN 80S AND 90S/100S.

TEMPS WILL GRADUALLY RETURN TO NORMAL WED-THU...THEN TURN HOT FOR 1-
2 DAYS FRI-SAT BEFORE TEMPS RETURN TO NORMAL AND POTENTIALLY TURN
MUCH COOLER THAN NORMAL NEXT WEEK. BASED ON THE PATTERN RAINFALL
WILL BE AT OR BELOW NORMAL THRU NEXT MON FOR MOST LOCATIONS.

SURFACE: COMFORTABLE HIGH PRES WILL SLIDE ACROSS THE CNTRL/NRN
PLAINS TUE NIGHT WITH RETURN FLOW AND A LEE-SIDE TROF DEVELOPING
WED. THE COOL FRONT THAT MOVES THRU TONIGHT WILL GRADUALLY LIFT BACK
N AS A WARM FRONT. THIS EVOLUTION WILL INITIATE A PATTERN OF WARM
AIR ADVECTION /WAA/ WITH PERIODIC CHANGES FOR SPOTTY SHWRS/TSTMS.
THE WARM FRONT THRU BE N OF THE FCST AREA FRI. THE NEXT COOL FRONT
FOLLOWS SOME TIME SAT OR SUN. THE EC/GFS/GEM ALL DISAGREE ON TIMING.
HIGH PRES WILL ASSERT ITSELF MON.

HAZARDS: MULTIPLE CHANCES FOR SPOTTY TSTM ACTIVITY EXIST...BUT THEY
WILL NOT ALL PAN OUT. WHILE CONFIDENCE IS LOW ON ANY SPECIFIC
CHANCES...PROBABLY THE "BEST" CHANCE IS 12 AM WED-12 PM THU WHEN
SOME HELP IS AVAILABLE ALOFT.

THE DAILY DETAILS...

TUE NIGHT: GOOD RADIATING. A GREAT NIGHT TO OPEN UP THE WINDOWS.

WED: INCREASING CLOUDS. VARIOUS MODELS AND MODEL RUNS KEEP TRYING TO
GENERATE SOME SPOTTY LIGHT PRECIP IN THETA-E ADVECTION. IT JUST
LOOKS TOO SOON TO ME. THIS COULD END UP JUST MID-LEVEL SPRINKLES IF
ANYTHING OCCURS AT ALL. MULTI-MODEL CROSS SECTIONS ALL HAVE A DECK
OF MID-LEVEL CLOUDS AROUND 10K FT.

WED NIGHT: A LOW-LVL JET DEVELOPS AND WHILE WE COULD SEE SOME VERY
SPOTTY SHWR/TSTM ACTIVITY IN THE ISENTROPIC ASCENT...THE BEST
CONVERGENCE WILL ALONG THE NEB BORDER INTO SD. FOR THIS BEING THE
"BEST" CHANCE...THE SREF QPF PROBABILITIES ARE POOR.

THU: SOME SHWR/TSTM ACTIVITY COULD BE LEFT OVER...ESPECIALLY E OF
HWY 281. THIS CONTS TO COMPLICATE THE TEMP FCST. AREAS BEHIND THE
WARM FRONT /W OF HWY 281/ COULD BE HOTTER THAN WE HAVE FCST...AND
AREAS E COULD BE COOLER.

THU NIGHT: LLJ RE-STRENGTHENS WITH MCS DEVELOPMENT PROBABLE AT ITS
NOSE...MOST LIKELY JUST N AND E OF THE FCST AREA.

FRI: WARM SECTOR. SUNNY/HOT AND CAPPED. ENVISION THAT WE WILL NEED
TO INCREASE HIGHS ANOTHER 3-5F. WE ARE CURRENTLY ADVERTISING 91-99F.

SAT-MON: DIFFICULT TO PROVIDE DETAILS WITH MODEL DISPARITY. SUFFICE
TO SAY THAT THE NEXT FRONTAL PASSAGE WILL HEIGHTEN THE RISK FOR
NIGHTTIME MCS ACTIVITY TO ROLL THRU HERE.

FOR WHAT IT`S WORTH...THE 00Z EC HAD HIGH TEMPS AT GRI IN THE LOW
70S FOR 7/15-16. THESE VALUES ARE AT THE 25TH PERCENTILE OF THE
ENSENBLE SPREAD. THE 12Z GFS OFFERS MID 70S IN THE 17TH-18TH TIME
FRAME. A LOT CAN CHANGE BETWEEN NOW AND THEN. JUST TRYING TO GIVE
YOU A FEEL FOR WHAT WE ARE CURRENTLY SEEING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1241 AM CDT TUE JUL 8 2014

VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THROUGH THE VALID
PERIOD. IN THE WAKE OF THUNDERSTORMS...SKIES ARE CLEARING AND
SHOULD BE MOSTLY CLEAR THROUGHOUT MOST OF THE DAY TUESDAY. WIND
SPEEDS WILL BE THE MAIN CONCERN...WITH SPEEDS PICKING UP BY MID
MORNING TO AROUND 10 TO 15 KNOTS. GUSTS WILL LIKELY BE CLOSER TO
20 KNOTS. THE WIND WILL BECOME LIGHT AND VARIABLE AROUND 7 PM WITH
MOSTLY CLEAR SKIES.

&&

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

$$

SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...GUERRERO



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