Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 111151
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
651 AM CDT THU SEP 11 2014

...RECORD COOL HIGH TEMPS TODAY FOLLOWED BY VERY CHILLY RAIN
TONIGHT THEN A SLOW CLIMB AS TEMPS ATTEMPT TO CLAW THEIR WAY BACK
TO NORMAL BY THE MIDDLE OF NEXT WEEK...

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 651 AM CDT THU SEP 11 2014

ALOFT: 00Z UPPER-AIR DATA AND AIRCRAFT OBS SHOWED A BROAD TROF
WAS OVER THE CNTRL USA WITH ITS AXIS ALONG 104 DEG W. THE CORE OF
THE COLDEST AIR ALOFT WAS OVER SW CANADA. A 110 KT JET STREAK WAS
ASSOCIATED WITH THIS COLD POCKET/TROF. THIS +TILT TROF WILL SAG
INTO THE NRN ROCKIES/PLAINS TODAY INTO TONIGHT AND WILL BE LOCATED
FROM MN-SD-NEB-WY BY DAYBREAK FRI. AS THE CURRENT GULF OF AK TROF
MOVES ONSHORE INTO WRN CANADA...THIS WILL DECREASE THE WAVELENGTH
OF THE TROF APPROACHING HERE...SUBSTANTIALLY INCREASING THE
DIVERGENCE ALOFT.

SURFACE: A CHILLY CONTINENTAL POLAR AIR MASS WAS IN PLACE OVER
THE NRN/CNTRL PLAINS. THE PRIMARY POLAR FRONT WAS WELL S AND E OF
THE FCST AREA...WITH ITS WESTERN EXTENT BANKED UP AGAINST THE
ROCKIES. ANOMALOUSLY STRONG HIGH PRES /3 STANDARD DEVIATIONS ABOVE
NORMAL/ WAS OVER ALBERTA. THIS HIGH WILL SLOWLY SINK S INTO MT
TODAY AND INTO WY TONIGHT.

THRU SUNRISE: CLOUDY WITH PATCHY LIGHT RAIN CONTINUING E PRIMARILY
N OF I-80. WHILE THE OVERALL TREND HAS BEEN FOR A DECREASE IN
COVERAGE. HOWEVER...SHWRS HAVE BEEN INCREASING TO THE SW BETWEEN
LXN AND LBF. POPS HAVE BEEN RE-ADJUSTED TO ACCT FOR THIS OVER THE
NEXT 3-4 HRS.

TODAY: CLOUDY AND UNSEASONABLY CHILLY WITH RECORD-BREAKING COOL
HIGH TEMPS. IN FACT...TODAY`S HIGHS WILL BE AT OR BELOW WHAT
NIGHTTIME LOW TEMPS SHOULD BE FOR THIS TIME OF YEAR /50S/. PLEASE
SEE CLIMATE SECTION BELOW FOR THE DETAILS. SUFFICE TO SAY TODAY`S
TEMPS WILL BE MORE TYPICAL OF LATE OCT!

SOME SPOTTY LIGHT RAIN OR DRIZZLE WILL CONT TO BE POSSIBLE THRU
THE DAY...PRIMARILY N OF HWY 6. THE FCST MAY BE SOMEWHAT OVERDONE
ON THIS POSSIBILITY. ONCE THIS EARLY MORNING BATCH OF R/DZ
DEPARTS...MUCH OF THE DAY SHOULD REMAIN DRY IN MOST AREAS AS IN-
CLOUD ICE/PRECIP PRODUCTION WILL BE LIMITED.

GOES WV IMAGERY DOES SHOW A BAROCLINIC LEAF DEVELOPING OVER THE
DAKOTAS...INDICATIVE OF INCREASED LIFT ASSOCIATED WITH THE
APPROACHING JET. HOWEVER...THE 06Z NAM CONTS TO SUGGEST PRECIP
PRODUCTION WILL BECOME INEFFICIENT OVER THE NEXT 3-6 HRS (IE -
DRY IN THE DGZ).

USED BIAS CORRECTED BLEND OF THE PREVIOUS GID FCST AND 00Z MODEL
2M TEMPS /BC-RAWBLEND/. THE 18Z/00Z NAM/GFS SKY FCSTS WERE TOO
OPTIMISTIC TRYING TO BREAK UP THE CLOUDS OVER THE SE FRINGE OF THE
FCST AREA. THIS WAS DISREGARDED AND SO BC-RAWBLEND TEMPS WERE
LOWERED 2-4F OVER N-CNTRL KS WHERE THEY APPEARED TO BE TOO HIGH.

TONIGHT: CLOUDY WITH A CHILLY RAIN DEVELOPING. SHOULD SEE A SOLID
W-E OR SW-NE ORIENTED SWATH/BAND OF RAIN DEVELOP FROM THE
SANDHILLS INTO THE PANHANDLE AND SINK SE INTO THE FCST AREA.

THIS WILL BE DRIVEN BY A BAND OF 700-500 MB FRONTOGENESIS WITHIN
AND JUST AHEAD OF THE UPPER TROF SAGGING INTO THE FCST AREA.
SYNOPTIC SCALE LIFT WILL BE SUPERIMPOSED ON THIS FRONTOGENETIC
LIFT/CIRCULATION VIA A STRONG PULSE OF QG FORCING IN THE RIGHT
REAR QUADRANT OF THE 110 KT JET. THE MID-UPPER LEVELS WILL
SATURATE AS A RESULT...WITH SIGNIFICANT/DEEP LIFT IN THE IDEAL
PRECIP FORMATION ZONE.

THUNDER?: CANT COMPLETELY RULE IT OUT BUT CONFIDENCE IS NOT HIGH
ENOUGH TO HAVE IN THE FCST. CROSS SECTIONS DO SHOW SOME WEAK
POTENTIAL INSTABILITY FOR UPRIGHT CONVECTION.

USED CONSENSUS OF MODEL 2M TEMPS/DWPTS /CONS-RAW/ DUE TO EXTENSIVE
CLOUD COVER. MOS TENDS TO ALLOW TEMPS TO COOL TOO MUCH AND ALLOWS
FOR UNREALISTIC TEMP-DWPT SPREADS TO OPEN UP IN SITUATIONS LIKE
THIS /FALLING PRECIP/.


.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 410 AM CDT THU SEP 11 2014

THE BIG STORY WILL CENTER AROUND THE MUCH BELOW NORMAL
TEMPERATURES THAT ARE EXPECTED THE NEXT FEW DAYS. IN ADDITION...
THE COLD RAIN THURSDAY NIGHT MAY PERSIST FOR SEVERAL HOURS INTO
FRIDAY MORNING.

FRIDAY...NORMAL HIGH TEMPERATURES FOR THIS TIME OF YEAR RANGE
FROM AROUND 80 OVER SOUTHERN NEBRASKA TO THE LOWER AND EVEN MID
80S ACROSS NORTHERN KANSAS. AN UPPER LEVEL TROUGH WILL SWING
THROUGH THE NORTHERN PLAINS AND A COLD AREA OF SFC HIGH PRESSURE
AT GREATER THAN 1030 MB WILL MOVE INTO THE REGION. THIS COLD AREA
OF HIGH PRESSURE COMING TO US OUT OF CANADA WILL RESULT IN
AFTERNOON HIGHS OF 25 TO 30 DEGREES BELOW NORMAL...WHICH
TRANSLATES INTO LOWER TO MIDDLE 50S FOR HIGHS. THIS IS A VERY
DYNAMIC SYSTEM COMING THROUGH AND THE FAVORABLE FRONTOGENESIS AREA
WILL SLIDE EAST ACROSS OUR FORECAST AREA THROUGH THE MORNING HOURS
WITH PRECIPITATION COMING TO AN END FROM WEST TO EAST AS WE HEAD
THROUGH THE MORNING. BY THE TIME THE PRECIPITATION COMES TO AN END
THERE IS PRETTY GOOD CONFIDENCE THAT MOST AREAS WILL HAVE RECEIVED
BETWEEN 0.25 AND 0.75 INCHES OF STORM TOTAL RAINFALL.

FRIDAY NIGHT...OUR ATTENTION WILL QUICKLY TURN TOWARDS AT LEAST
THE LIMITED THREAT OF A FROST IN LOW LYING RURAL AREAS LATE FRIDAY
NIGHT/EARLY SATURDAY MORNING. THE SFC HIGH WILL LIKELY BE LOCATED
DIRECTLY OVERHEAD DURING PART OF THE NIGHT...BUT MAY SLIDE JUST
EAST OF OUR FORECAST AREA BY AROUND DAWN ON SATURDAY.
HOWEVER...THE SFC HIGH WILL BE CLOSE ENOUGH TO RESULT IN FAVORABLE
CONDITIONS FOR STRONG RADIATIONAL COOLING DUE TO LIGHT WINDS AND
MOSTLY CLEAR SKIES. WE ARE CURRENTLY CALLING FOR LOWS IN THE MID
30S ACROSS THE FORECAST AREA. IT IS IMPORTANT TO REMEMBER THAT SFC
TEMPERATURE READINGS ARE TAKEN AT 2M OFF THE GROUND AND DURING
TIMES OF FAVORABLE RADIATIONAL COOLING THE TEMPERATURE RIGHT AT
THE GROUND OR IN LOW SPOTS SUCH AS RIVER VALLEYS AND DITCHES COULD
BE A FEW DEGREES COOLER. THEREFORE...IT IS CONCEIVABLE THAT WE
COULD SEE WHAT WOULD AMOUNT TO A RATHER EARLY PATCHY FROST LATE
FRIDAY NIGHT INTO EARLY SATURDAY MORNING...MAINLY IN LOW LYING
RURAL AREAS.

SATURDAY AND SUNDAY...LOOK GREAT AS RETURN SOUTHERLY FLOW ALLOWS
TEMPERATURES TO GRADUALLY MODERATE FROM THE LOWER TO MID 60S ON
SATURDAY INTO THE LOW TO MID 70S ON SUNDAY WITH DRY CONDITIONS AND
PLENTY OF SUNSHINE.

SUNDAY NIGHT THROUGH MONDAY NIGHT...A WEAKER UPPER LEVEL SHORT
WAVE WILL TRACK ACROSS THE NORTHERN PLAINS WITH A WEAK SFC TROUGH
AXIS CROSSING OUR AREA. THIS WILL RESULT IN A LOW END CHANCE OF A
FEW SHOWERS OR ISOLATED THUNDERSTORMS...BUT NOT EXPECTING MUCH AT
THIS POINT IN TIME AND COVERAGE COULD BE RATHER LIMITED.
TEMPERATURES WILL REMAIN FAIRLY STEADY WITH HIGHS RANGING FROM
AROUND 70 NEBRASKA TO THE MID 70S KANSAS. OVERNIGHT LOWS WILL
INCREASE WITH MORE CLOUDS AND MOISTURE IN THE AIR AND SHOULD RANGE
FROM THE UPPER 40S TO THE LOWER 50S.

TUESDAY AND WEDNESDAY...THE MILD WEATHER WILL CONTINUE WITH HIGHS
GENERALLY IN THE 70S. FORECAST MODELS DIFFER ON THE TIMING OF WEAK
SHORT WAVES IN THIS PERIOD. THERE IS A SLIGHT CHANCE OF A RAIN
SHOWER OR ISOLATED THUNDERSTORM DEPENDING ON THE TRACK AND TIMING
OF THE NEXT SHORT WAVE...BUT AT THIS POINT IN TIME ODDS ARE MORE
LIKELY THAT MOST AREAS WILL BE DRY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 651 AM CDT THU SEP 11 2014

CONFIDENCE THRU 12Z/FRI: MEDIUM DUE TO UNCERTAINTY ON CIG HEIGHTS
AND ANY TIMING OF CHANGES IN CIG HEIGHTS FROM ONE FLGT CATEGORY TO
ANOTHER.

TODAY: IFR STRATUS CIGS SHOULD LIFT TO LOW-END MVFR 15Z-18Z AND
POSSIBLY TO HIGH-END MVFR 19Z-22Z BUT THIS LATTER POSSIBILITY IS
THE LOWEST CONFIDENCE PORTION OF THIS FCST. PATCHY -DZ/-RA MOVES
THRU FROM TIME TO TIME. NNE WINDS 10-15 KTS.

TONIGHT: MVFR DEGRADES BACK DOWN TO IFR CIGS/VSBYS AS STEADY -RA
MOVES IN 04Z-06Z WITH SOME POSSIBILITY OF CIGS LOWERING TO LIFR.
N WINDS AROUND 10 KTS.

&&

.CLIMATE...
ISSUED AT 410 AM CDT THU SEP 11 2014

THURSDAY IS PRETTY MUCH ASSURED TO BE THE COOLEST SEPT 11TH EVER
RECORDED IN 100+ YRS OF RECORDS AT GRAND ISLAND (GRI) AND HASTINGS
(HSI). THE PERIOD OF RECORD FOR TEMPS AT GRI IS 1895- PRESENT. HSI
1907-PRESENT.

              RECORD COOL      NORMAL     NORMAL     TODAY`S
LOCATION       HIGH TEMP     HIGH TEMP   LOW TEMP   HIGH TEMP

GRI           57 IN 1989         80          55         54
HSI           57 IN 1924         79          56         54

RECORD COOL HIGH TEMP ALSO LOOKS PROBABLE TOMORROW BUT ONLY AT
HSI. GRI IS SAFELY OUT OF REACH:

GRI  46 IN 1989 (CURRENT FCST: 54)
HSI  56 IN 1989 (CURRENT FCST: 53)

&&

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

$$

SHORT TERM...HALBLAUB
LONG TERM...WESELY
AVIATION...HALBLAUB
CLIMATE...HALBLAUB


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