Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 251008
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
508 AM CDT MON AUG 25 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM CDT MON AUG 25 2014

THE FOCUS IS ON THUNDERSTORMS IN AN ACTIVE WEATHER PATTERN TO START
THE WORKWEEK. THE PATTERN ALOFT ACROSS THE CENTRAL PLAINS
FEATURED SOUTHWEST FLOW WITH AN UPPER TROUGH LOCATED ACROSS THE
WESTERN CONUS WITH TWO DISTINCT LOW PRESSURE CENTERS...ALONG THE
ND/MANITOBA BORER AND IN OREGON...WHILE UPPER RIDGING WAS IN
PLACE FM OLD MEXICO THRU THE MISSISSIPPI/OHIO VALLEY REGIONS. AT
THE SURFACE WE HAVE A PSEUDO STATIONARY WARM FRONTAL BOUNDARY WAS
ORIENTED ACROSS NORTHERN KANSAS...WHILE TO THE NORTH THERE IS A
DISTINCT BOUNDARY NOTED ON KLNX RADAR WORKING SOUTH OF THEDFORD IN
NW NEB AS A SFC RIDGE BUILDS SOUTHEAST ALONG THE NEB/SD STATELINE.

CONVECTION DEVELOPED DURING THE LATE EVENING ACROSS CO AND THIS
ACTIVITY IS WORKING EASTWARD THIS MORNING FM WESTERN KS EARLY AND
IS ON THE EDGE OF OUR WESTERN ZONES...MAINLY SOUTH OF INTERSTATE
80. THIS ACTIVITY WILL CONTINUE TO MIGRATE EAST NORTHEASTWARD
TODAY IN THE MEAN FLOW WITH THE BETTER CHCS FOR PCPN FOCUSED ACROSS
THE NW TWO THIRDS OF OUR CWA.

THE UPPER LOW PRESSURE SYSTEM IN OREGON WILL DIG INTO NV TODAY WITH
SW FLOW ALOFT FURTHER DEEPENING ACROSS THE PLAINS...WITH SEVERAL
SHORTWAVES LIFTING OUT OF THE WESTERN TROUGH.  THE FRONTAL
BOUNDARIES COMBINED WITH A PROLONGED PERIOD OF ISENTROPIC LIFT
WILL LEAD TO CHCS FOR STORMS THRU TONIGHT. THE DAYTIME HOURS MAY
NOT BE A COMPLETE RAIN OUT BUT WITH STORMS ONGOING...AND THE
POTENTIAL FOR ADDITIONAL DEVELOPMENT IN LIFT/DYNAMICS JUST CANNOT
LEAVE FORECAST DRY.

THE OVERNIGHT HOURS SHOULD SEE MORE WIDESPREAD CONVECTION NORTH OF
THE WARM FRONTAL BOUNDARY PRIMARILY ACROSS SOUTH CENTRAL NEBRASKA.
THE POTENTIAL EXISTS FOR SOME GOOD RAINFALL AMOUNTS AS PRECIPITABLE
WATER VALUES AVERAGE AN INCH AND HALF.  CANNOT RULE OUT THE
CHANCE FOR STRONG TO SEVERE STORMS NEAR THE FRONT THIS
EVENING/TONIGHT AS THE HIGHER MOISTURE/INSTABILITY POOLS ALONG THE
FRONT NEAR THE NEB/KS STATELINE. WILL CONTINUE TO MENTION
POSSIBILITY OF SEVERE STORMS IN THE HWO.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 508 AM CDT MON AUG 25 2014

RIGHT OFF THE TOP...WANT TO CONFESS THAT THIS LONG TERM SECTION
IS WRITTEN FROM THE PERSPECTIVE OF A FORECASTER WHO HAS BEEN VERY
OUT OF TOUCH WITH RECENT FORECAST TRENDS REGARDING THIS 6-DAY TIME
FRAME...BUT IF NOTHING ELSE THIS SHOULD PROVIDE A FRESH FIRST
IMPRESSIONS PERSPECTIVE. AND SPEAKING OF FIRST IMPRESSIONS...THE
INITIAL QUESTION THAT CAME TO MIND WHEN PERUSING THE LARGE-SCALE
MID-UPPER PATTERN THROUGH THIS WEEKEND WAS: WHAT MONTH REALLY IS
THIS? INSTEAD OF WHAT CAN OFTEN BE A FAIRLY RIDGE-DOMINATED AND
GENERALLY DRIER PATTERN THIS TIME OF YEAR (WITH LATE LAST AUGUST
BEING A PRIME EXAMPLE)...INSTEAD WE ARE LOOKING AT A QUITE ACTIVE
AND FOR SOME/MOST PLACES A RATHER WET WORK WEEK AS A LARGE SCALE
TROUGH IN THE WESTERN CONUS GRADUALLY WORKS ITS WAY EASTWARD INTO
THE CENTRAL PLAINS BY LATE IN THE WEEK...AND MAYBE...JUST MAYBE
WILL BE FAR ENOUGH EAST TO PROVIDE HIGHER CONFIDENCE IN A DRY
WEEKEND...ALTHOUGH EVEN THIS IS STARTING TO COME IN QUESTION
SOMEWHAT ESPECIALLY FOR SATURDAY PER THE LATEST ECMWF SOLUTION.

SO...TO SUMMARIZE THE BIG PICTURE...THE ENTIRE TUESDAY DAYTIME-
FRIDAY NIGHT TIME FRAME CONTAINS A PARADE OF AT LEAST 20-40
PERCENT POPS...WITH THE OVERALL-HIGHEST 60-70 POPS CONCENTRATED IN
THE TUESDAY AND WEDNESDAY EVENING/NIGHT TIME FRAMES AND AT LEAST
SLIGHTLY FAVORING NEBRASKA PORTIONS OF THE CWA VERSUS KS. ALTHOUGH
SATURDAY DAYTIME STILL REMAINS VOID OF ANY FORMAL PRECIP
MENTION...SILENT 10 PERCENT POPS ARE FIRMLY IN PLACE DEPENDING ON
HOW THE SPEED/TRACK OF THE MID LEVEL TROUGH AXIS BEHAVES.

AS FOR SEVERE WEATHER PROSPECTS...ALTHOUGH NO TIME FRAMES APPEAR
TO FEATURE A TRULY CONCERNING COMBINATION OF LARGE SCALE FORCING
AND CAPE/SHEAR...THE POTENTIAL FOR 1500-2000+ J/KG CAPE IN THE
PRESENCE OF AROUND 30KT OF DEEP LAYER WIND SHEAR CERTAINLY
SUPPORTS THE POTENTIAL FOR AT LEAST A SMATTERING OF STRONG TO
MARGINALLY SEVERE STORMS ESPECIALLY DURING THE LATE
AFTERNOON/EVENING TIME FRAMES...AND CANNOT ARGUE WITH THE STORM
PREDICTION CENTER BROAD-BRUSHING THE ENTIRE CWA WITH 5 PERCENT
SEVERE PROBABILITIES ON THE LATEST DAY 2-3 OUTLOOKS FOR
TUESDAY/WEDNESDAY. OF COURSE A LATER UPGRADE TO A FORMAL SLIGHT
RISK AREA CANNOT BE COMPLETELY RULED OUT.

AS HAS BEEN COVERED IN RECENT DISCUSSIONS...IT VERY WELL MIGHT
TURN OUT THAT THE BIGGER STORY THIS WEEK COULD BE MULTIPLE ROUNDS
OF AT LEAST MODERATE TO HEAVY RAINFALL...AS WEAK MID LEVEL
DISTURBANCES TRACK ACROSS THE AREA AND TEAM WITH AT LEAST MODEST
EVENING/OVERNIGHT ENHANCEMENTS IN THE LOW LEVEL JET EVIDENT AT 850
MILLIBARS TO FOCUS FAIRLY WIDEPSREAD SHOWER/THUNDERSTORM ACTIVITY
ALONG AND ESPECIALLY JUST NORTH OF A QUASI-STATIONARY/GENERALLY
EAST-WEST ORIENTED SURFACE FRONT THAT WAVERS AROUND AT LEAST
THROUGH MID-WEEK WITHIN OR NEAR THE SOUTHERN CWA. FROM A
VERY...VERY GENERAL PERSPECTIVE...THIS PATTERN APPEAR RIPE TO
YIELD A FAIRLY WIDESPREAD COVERAGE OF 2-3+ INCH RAIN TOTALS BY
WEEKS END ACROSS A FAIRLY DECENT CHUNK OF THE CWA...WITH LOCALLY
HIGHER AMOUNTS VERY POSSIBLE IF NOT LIKELY IN PLACES WHERE
MULTIPLE ROUNDS OF RAIN HAPPEN TO TRACK. OF COURSE...PINPOINTING
THESE EXACT SWATHS OF HEAVIEST RAIN POTENTIAL IS VIRTUALLY
IMPOSSIBLE MORE THAN 12-24 HOURS IN ADVANCE...AND DEPENDING ON
MESOSCALE DETAILS IT VERY WELL MIGHT TURN OUT THAT THE HEAVIEST
RAIN COULD GET SPACED OUT FAIRLY EVENLY IN AREAL COVERAGE ON A
DAILY OR EVERY-OTHER-DAY BASIS...THUS MINIMIZING FLOODING
POTENTIAL. HOWEVER...AT LEAST MINOR FLOODING OF LOW LYING AREAS
AND STREAMS IS VERY POSSIBLE SHOULD THE SAME PARTICULAR COUNTIES
RECEIVE 1-2+ INCHES OF HEAVY RAIN WITHIN A 24-36 HOUR PERIOD...AND
ALTHOUGH THE SOIL IS LIKELY PRIMED TO HANDLE AT LEAST A FEW INCHES
OF RAIN EARLY IN THE WEEK WITH FEW HYDRO CONCERNS...ITS NOT OUT
OF THE QUESTION THAT SOMEWHAT MORE CONCERNING HYDRO ISSUES COULD
EVOLVE ESPECIALLY BY THE WED-THURS TIME FRAME IF RAIN REALIZES ITS
FULL POTENTIAL. THE BOTTOM LINE...FAR TOO EARLY FOR ANY TYPE OF
FORMAL FLOOD WATCH...BUT WILL CONTINUE TO CARRY SOME FLOODING
CONCERNS IN THE HAZARDOUS WEATHER OUTLOOK.

AS IF FORECASTING RAIN/THUNDERSTORM COVERAGE AND POPS IS NOT
CHALLENGING ENOUGH...IT ALSO FOLLOWS THAT CONFIDENCE IN
TEMPERATURES THROUGH THE WEEK...NAMELY HIGHS...IS NOT ALL THAT
STELLAR AS WELL GIVEN THE POTENTIALLY WIDELY VARYING SCENARIOS ON
HOW MUCH DAYTIME PRECIP/CLOUD COVER MIGHT OCCUR...OR LACK THEREOF.
IN PARTICULAR...HIGHS ON BOTH TUESDAY AND WEDNESDAY REFLECT A
SOLID 10-15 DEGREE GRADIENT RANGING FROM ONLY MID-UPPER 70S NORTH
TO UPPER 80S/LOW 90S SOUTH...AND DEPENDING ON WHERE THE SURFACE
FRONT LINES UP COULD EVEN SEE FAR SOUTHERN AREAS JUMP WARMER THAN
THIS INTO THE MID 90S. BEYOND WEDNESDAY...THE TEMPERATURE
FORECAST DOES NOT REFLECT AS SHARP OF A GRADIENT (AT LEAST FOR
NOW)...BUT GENERALLY REFLECTS MOST OF THE CWA TOPPING OUT
SOMEWHERE IN THE 80S THROUGH THIS WEEKEND.

NO TIME TO DIVE INTO THE USUAL DAILY DETAILS ON THIS SHIFT...BUT
GIVEN THE LIKELIHOOD THAT DAY-TO-DAY MESOSCALE INFLUENCES MAY IN
SOME CASES SIGNIFICANTLY AFFECT FORECAST DETAILS AS PARTICULAR
DAYS/NIGHTS TRANSITION FROM THE MID TERM INTO THE SHORT TERM TIME
FRAME...ITS PROBABLY BEST THAT WE FOCUS ONLY ON THE
BROADER/LARGER-SCALE STORY FOR NOW ANYWAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1141 PM CDT SUN AUG 24 2014

QUIET WEATHER IS EXPECTED UNTIL THE LATTER HOURS OF THE TAF
PERIOD WHEN CHANCES FOR THUNDERSTORMS INCREASE.

&&

.CLIMATE...
ISSUED AT 508 AM CDT MON AUG 25 2014

NEEDLESS TO SAY...THE DOOR IS WIDE OPEN FOR A DECENT CHUNK OF THE
CWA TO END UP WITH A TOP-10 WETTEST AUGUST ON RECORD...AND SOME
LOCATIONS HAVE LIKELY REACHED THAT MARK ALREADY. HERE IS WHERE
THINGS CURRENTLY STAND AT OUR TWO PRIMARY CLIMATE SITES GRAND
ISLAND/HASTINGS AIRPORTS...WITH OVER 6 FULL DAYS TO GO IN THE
MONTH:

- GRAND ISLAND: 4.27 INCHES SO FAR THIS MONTH...CURRENTLY STANDS
AS 23RD-WETTEST OUT OF 119 YEARS DATING TO 1896...AND MUST RECEIVE
AT LEAST 1.51 MORE INCHES TO BREAK INTO THE AUGUST TOP-1O. WETTEST
AUGUST ON RECORD WAS 8.73 INCHES IN 1977.

- HASTINGS: 5.69 INCHES SO FAR THIS MONTH...CURRENTLY STANDS AS
13TH-WETTEST OUT OF 120 YEARS DATING TO 1895...AND ONLY NEEDS 0.62
MORE INCHES TO BREAK INTO THE AUGUST TOP-10 AND 2.08 MORE TO BREAK
INTO THE AUGUST TOP-5. WETTEST AUGUST ON RECORD WAS 9.86 INCHES IN
1903.

&&

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

$$

SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...FAY
CLIMATE...PFANNKUCH


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