Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 171804 AAA
AFDGID

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HASTINGS NE
104 PM CDT FRI APR 17 2015

.UPDATE...
UPDATE ISSUED AT 104 PM CDT FRI APR 17 2015

SATELLITE SHOWS THE LEADING EDGE OF THE DRY SLOT /LOWER THETA-E
AIR ALOFT/ LIFTING N ACROSS THE FCST AREA. FCST SOUNDINGS SUGGEST
THIS IS MORE DRYING ALOFT THAN COOLING. SO EXPECT NO SIGNIFICANT
INCREASE IN POTENTIAL INSTABILITY. THERE ARE NO EASY CLUES AS TO
WHERE SHWRS/TSTMS WILL REDEVELOP...BUT SATELLITE TRENDS SUGGEST AN
ARC ACROSS WRN KS THAT WILL EVENTUALLY LIFT N INTO THE FCST AREA
THIS EVE/TONIGHT.

THE 12Z NMM/ARW WRF LEND SUPPORT TO THIS SCENARIO ALONG WITH THE
09Z SREF QPF PROBABILITIES.

WE AGREE WITH SPC ASSESSMENT OF SVR POTENTIAL. IT WILL MAINLY BE
FOCUSED SW OF THE FCST AREA WITH THE INITIAL DEVELOPMENT. SOME OF
THIS COULD MAINTAIN ITS POTENCY INTO FAR SW PORTIONS OF THE FCST
AREA /S OF A LINE FROM BEAVER CITY NE TO OSBORN KS/.

PLEASE SEE 1258 PM MESO DISCUSSION FROM SPC.

DESPITE SUBSTANTIAL SHEAR...MLCAPE WILL STRUGGLE TO REACH 1500
J/KG. THE COOL AIR ALOFT WILL RESULT IN ENOUGH STORMS TO ALLOW
FOR INTERACTIONS AND MERGERS. SO WHILE SOME SUPERCELLS MAY BE
EMBEDDED IN THE INTIAL DEVELOPMENT...EXPECT MORE LINEAR STRUCTURES
IN OUR FCST AREA. SO SVR THREAT WILL BE LIMITED BUT NOT ZERO.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT FRI APR 17 2015

NO SIGNIFICANT CHANGES FROM PREVIOUS THINKING THROUGH THE SHORT
TERM PERIODS AS AN UPPER LEVEL LOW ACROSS THE DESERT SOUTHWEST
WILL SLOWLY LIFT NORTHEASTWARD OVER THE NEXT 24 HOURS...WITH A
NEAR CONTINUOUS STREAM OF MOISTURE FORECAST TO MOVE ACROSS THE
LOCAL AREA. WITH AMPLE MOISTURE...AND MODEST INSTABILITY...EXPECT
TO SEE SHOWERS AND THUNDERSTORMS DEVELOP AND MOVE ACROSS THE LOCAL
AREA FROM TIME TO TIME...AS WEAK PERTURBATIONS ROTATE AROUND THIS
UPPER LEVEL LOW.

DESPITE ONLY MODEST INSTABILITY...ON THE ORDER OF 1000 J/KG...
THANKS TO MARGINAL SHEAR VALUES AND PLENTY OF MOISTURE TO WORK
WITH...EXPECT THE POSSIBILITY FOR SOME STRONG TO POTENTIALLY
SEVERE THUNDERSTORMS TO DEVELOP LATER THIS AFTERNOON AND
EVENING WITH ANY OF THE STRONGER VORT MAXES ROTATING AROUND THE
UPPER LOW...WITH LARGE HAIL BEING THE PRIMARY HAZARD. AND WHILE
THE BEST INSTABILITY AND SHEAR VALUES WILL BE SITUATED ACROSS
NORTH CENTRAL KANSAS...AND HENCE THE BEST CHANCE FOR ANY SEVERE
WEATHER...IN REALITY...STRONG TO MARGINALLY SEVERE THUNDERSTORMS
WILL BE POSSIBLE ACROSS THE ENTIRE FORECAST AREA THIS AFTERNOON
AND EVENING. IN FACT...THE LATEST SPC OUTLOOK HAS EXPANDED THE
AREA OF SLIGHT RISK NORTHWARD AS WELL AS ADDED AN ENHANCED RISK OF
SEVERE WEATHER ACROSS PORTIONS OF NORTH CENTRAL KANSAS IN THE 06Z
OUTLOOK.

OTHERWISE...PLENTY OF CLOUD COVER AND SHOWER ACTIVITY WILL HELP TO
HOLD DOWN TEMPERATURES THIS AFTERNOON A FEW DEGREES BELOW
YESTERDAYS VALUES...BUT IN GENERAL...AFTERNOON TEMPERATURES WILL
REMAIN VERY SEASONABLE FOR THIS TIME OF YEAR. THEN...THANKS TO THE
ELEVATED DEWPOINTS AND VERY LITTLE CHANGE IN THE OVERALL
AIRMASS...EXPECT ANOTHER NIGHT OF MILD TEMPERATURE READINGS...WITH
LOWS GENERALLY FORECAST TO BE IN THE 50S ACROSS THE LOCAL AREA.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 346 AM CDT FRI APR 17 2015

THE UPPER LEVEL LOW WILL MOVE ONTO THE HIGH PLAINS SATURDAY...THEN
INTO KANSAS SATURDAY NIGHT. ON SUNDAY THE UPPER LOW OPENS A LITTLE
AND MOVES ON TO THE EAST OF THE AREA.

SHOWERS AND THUNDERSTORMS ARE POSSIBLE SATURDAY AS THE UPPER LOW
APPROACHES THE AREA. THE BEST CHANCE FOR THUNDERSTORMS WILL BE
DURING THE AFTERNOON AND INTO THE EVENING WHEN THE MUCAPE IS 1000 TO
1300 J/KG. EXPECT SHOWERS TO CONTINUE INTO SUNDAY. THERE ARE A FEW
TIMING CONCERNS WITH THE SHOWERS ON SUNDAY. THE NAM IS A LITTLE
FASTER TO MOVE THE UPPER LOW TO THE EAST OF THE AREA AND MOVE
PRECIPITATION OUT OF THE AREA. SINCE BOTH THE GFS AND ECMWF HAVE
PRECIPITATION CONTINUE INTO SUNDAY AFTERNOON SO WILL KEEP THE POPS
ACROSS THE AREA.

BEHIND THE UPPER LOW COOLER AIR PUSHES INTO THE AREA. THERE COULD BE
A GOOD BREEZE ON SUNDAY FROM THE NORTHWEST AND FEEL COOLER THAN THE
NEAR 60 TEMPERATURES. ESPECIALLY WITH SOME CLOUDS AND SOME SHOWERS.
A SURFACE HIGH PRESSURE SYSTEM PUSHES INTO THE AREA SUNDAY NIGHT AND
MONDAY. THE CLEARING SKIES AND LIGHTER WINDS WILL ALLOW TEMPERATURES
TO COOL INTO THE 30S. TEMPERATURES WILL START A SLOW WARMING TREND
FOR TUESDAY AND WEDNESDAY.

MODELS HAVE A FEW DIFFERENCES FOR WEDNESDAY THROUGH THURSDAY. BOTH
HAVE AN UPPER LOW IN THE GREAT LAKES AREA AND A WEAK RIDGE IN THE
WESTERN CONUS. THE GFS BRINGS A WEAK WAVE THROUGH THE RIDGE WHILE
THE ECMWF HAS AN EVEN WEAKER WAVE FURTHER SOUTH. THE GFS THEREFORE
KEEPS PRECIPITATION ACROSS THE AREA. WILL KEEP SOME POPS ACROSS THE
AREA BUT WILL HAVE TO WATCH TO SEE WHERE THE UPPER WAVE COMES
THROUGH THE PLAINS.

&&

.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z SAT AFTERNOON)
ISSUED AT 101 PM CDT FRI APR 17 2015

THIS AFTERNOON: VARIABLE MOSTLY VFR CIGS...BUT TEMPORARY MVFR CIGS
AND MVFR/IFR SHWRS WILL BE POSSIBLE. SHWRS AND ISOLATED TSTMS
COULD DEVELOP AT ANY TIME...BUT THE BEST CHANCE WILL BE AFTER 21Z.
IT IS IMPOSSIBLE TO PROVIDE SPECIFIC TIMING FOR SHWRS/TSTMS SO
WATCH FOR AMENDMENTS...IF WE CAN GET A HANDLE ON SHORT-TERM
TRENDS. E WINDS 7-15 KTS. CONFIDENCE: MEDIUM

TONIGHT: VARIABLE MOSTLY VFR CIGS UNTIL 06Z. PROBABILITY FOR A
PERIOD OF IFR TSTMS IS HIGH...BUT PREFER TO NOT INCLUDE IN THE TAF
UNTIL WE ARE SURE THEY DEVELOP. LATEST SHORT-TERM GUIDANCE
SUGGESTS IFR FOG/STRATUS DEVELOP AFTER 06Z WITH DECREASING VSBYS/
CIGS ESPECIALLY AFTER 10Z. ESE WINDS LESS THAN 10 KTS. CONFIDENCE:
MEDIUM

SAT THRU 18Z: IFR FOG/STRATUS EVENTUALLY LIFTS TO VFR CU BY 18Z.
SE WINDS UNDER 10 KTS. CONFIDENCE: MEDIUM


&&

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

$$

UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...JCB
AVIATION...HALBLAUB



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