Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 242122
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
422 PM CDT THU APR 24 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 422 PM CDT THU APR 24 2014

A RED FLAG WARNING IS IN EFFECT UNTIL 7 PM FOR LOCATIONS WEST OF A
LINE FROM ORD TO LEXINGTON TO CAMBRIDGE WHERE LOW RELATIVE HUMIDITY
VALUES RANGE FROM 15 TO 20 PERCENT AND FUELS ARE FAVORABLE DUE TO
DRY CONDITIONS/LACK OF RAINFALL.  NORTHWEST WINDS WILL REMAIN GUSTY
FOR A FEW MORE HOURS BEFORE DROPPING OFF BY EVENING.

ALOFT...AN UPPER TROUGH WILL CONTINUE TO DEPART THE PLAINS TONIGHT
WITH HEIGHTS RISING INTO FRIDAY WITH SUBTLE RIDGING SETTLING ACROSS
THE PLAINS. THE AIRMASS WILL REMAIN DRY OVERNIGHT AND WITH GOOD
RADIATING CONDITIONS WE ARE LOOKING AT CHILLY TEMPS FOR LOWS...WITH
READINGS IN THE UPPER 30S/LOW 40S WHICH ARE ACTUALLY FAIRLY SEASONAL
FOR THIS TIME OF YEAR.

HEADING INTO FRIDAY...DRY CONDITIONS REMAIN AND TEMPERATURES WILL BE
ON THE INCREASE. SURFACE LOW PRESSURE DEEPENS ALONG THE HIGH PLAINS
REGION AND SOUTHERLY WINDS INCREASE DURING THE AFTN. H85 TEMPS ARE
PROGGED AROUND 17-18C WITH FORECAST SOUNDINGS SHOWING DEEP MIXING
ABOVE THIS LEVEL. TEMPS SHOULD CLIMB WELL INTO THE 70S TO THE LOWER
80S.  ALSO SOMETHING TO WATCH IS THE POTENTIAL FOR THE AFTERNOON
HOURS TO BE SNEAKY BREEZY DUE TO A TIGHTENING PRESSURE GRADIENT AS
THE SFC LOW DEEPENS AND EDGES EASTWARD...ALONG WITH THE DEEP MIXING
PROGGED. HAVE INCREASED WINDS ON FRIDAY AND WE ARE EDGING CLOSER TO
NEAR CRITICAL FIRE WEATHER CONDITIONS WITH LOW RELATIVE HUMIDITIES
PROGGED IN THE LOW 20TH PERCENTILE.  WILL HOLD OFF ON NEAR FIRE
WEATHER MENTION IN HWO FOR NOW WITH WINDS AND RELATIVE HUMIDITIES
MARGINAL AND WE STILL HAVE WET GROUND FROM THE RECENT RAINFALL BUT
LATER SHIFTS WILL NEED TO KEEP AN EYE ON THIS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 422 PM CDT THU APR 24 2014

NEEDLESS TO SAY...THIS 6-DAY PERIOD IS PROVING TO MAKE FOR A VERY
COMPLEX...CHALLENGING FORECAST...PRIMARILY DUE TO THE CONTINUED
UNCERTAINTY REGARDING THE EVOLUTION OF A FAIRLY CLASSIC...VERY
DEEP/DYNAMIC SPRING LOW PRESSURE SYSTEM INITIALLY SWINGING OUT OF
THE WESTERN CONUS INTO THE CENTRAL CONUS IN A
VIGOROUS...NEGATIVELY TILTED FASHION AND THEN STALLING
OUT/MEANDERING AROUND FOR A FEW DAYS THEREAFTER. AS A RESULT OF
THIS SYSTEM...THE OFFICIAL FORECAST NOW HAS 9 CONSECUTIVE PERIODS
BETWEEN SATURDAY AFTERNOON AND WEDNESDAY THAT CONTAIN AT LEAST AT
SLIGHT CHANCE OF PRECIPITATION FOR AT LEAST SOME PORTION OF THE
CWA. OF COURSE...ITS UNLIKELY THAT WIDESPREAD RAIN WILL DEVELOP ON
ALL OF THESE DAYS/NIGHTS...SO THERE IS A LOT OF FINE-TUNING TO DO
HERE. TEMPERATURE-WISE...CONFIDENCE AS USUAL IS A LITTLE HIGHER
THAN WITH PRECIPITATION...AND WE CONTINUE TO HAVE FAIRLY HIGH
CONFIDENCE THAT SATURDAY WILL NOW IN FACT BE THE WARMEST DAY OF
THESE 6 WITH UPPER 70S-UPPER 80S...WHILE A DECENT COOL-DOWN
FEATURING SLIGHTLY BELOW NORMAL HIGHS GENERALLY BETWEEN THE MID
50S-LOW 60S SETTLES IN FOR THE BALANCE OF THE WORK WEEK AS THE
SLOW-MOVING UPPER SYSTEM KEEPS LOW-LEVEL NORTHWESTERLY FLOW IN
PLACE THROUGH THIS TIME.

GETTING INTO HAZARDS POTENTIAL AND STARTING WITH THE PARAMOUNT
CONCERN OF SEVERE THUNDERSTORMS...THIS POSSIBILITY IS AS COMPLEX
AS ANY ELEMENT OF THE FORECAST. ON PAPER...THE VAST MAJORITY OF
THE CWA IS CURRENTLY HIGHLIGHTED FOR AT LEAST A SLIGHT RISK OF
SEVERE STORMS BY SPC ON BOTH SATURDAY (DAY 3) AND SUNDAY (DAY 4).
HOWEVER...SOME OF THE LATEST 12Z/18Z MODELS INCLUDING THE
NAM/ECMWF ARE QUITE HESITANT IN EVEN DEVELOPING ROBUST CONVECTION
WITHIN THE LOCAL AREA ON SATURDAY AFTERNOON/NIGHT...INSTEAD
FOCUSING THE MAIN THREAT AREA JUST OFF TO THE SOUTHEAST AND/OR
EAST OF THE LOCAL AREA...BUT IT COULD BE A CLOSE CALL. THEN FOR
SUNDAY...THERE ARE INCREASING SIGNALS THAT A SIGNIFICANT MID LEVEL
DRY SLOT AND LOW LEVEL DRY AIR INTRUSION FROM THE SOUTHWEST COULD
SHUT DOWN ANY SEVERE WEATHER RISK FOR MUCH OF THE SOUTHERN TO
SOUTHWEST HALF OF THE CWA...WHILE NORTH/NORTHEAST AREAS COULD
BE SETTING UP FOR AT LEAST A BRIEF BUT ACTIVE BOUT OF SEVERE
STORMS DURING THE AFTERNOON/EVENING...AS SOME SORT OF EAST-WEST OR
NORTHWEST-SOUTHEAST ORIENTED WARM FRONT SETS UP ACROSS THE
AREA...EXTENDING FROM A LIKELY VERY DEEP SURFACE LOW PRESSURE
SYSTEM ON THE ORDER OF 983 MILLIBARS THAT IS CURRENTLY EXPECTED TO
BE CENTERED SOMEWHERE IN THE WESTERN HALF OF NEBRASKA OR NEAR THE
NEB/KS/CO BORDER AT MID-DAY SUNDAY. ALTHOUGH THE SATURDAY-SUNDAY
TIME FRAME IS ONLY A FEW DAYS AWAY...ITS JUST TOO SOON YET TO
REALLY GAUGE THE MAGNITUDE OF THE LOCAL SEVERE WEATHER
THREAT...AND AS A RESULT THINGS HAVE BEEN KEPT PRETTY VAGUE TO
THIS POINT IN THE HAZARDOUS WEATHER OUTLOOK PRODUCT (HWO).
HOWEVER...FROM A PURELY SYNOPTIC PATTERN STANDPOINT...ANY
POTENTIAL SEVERE STORMS SATURDAY/SATURDAY NIGHT WOULD LIKELY BE A
PREDOMINANTLY HAIL/WIND THREAT...WHILE STORMS ON SUNDAY ALONG THE
WARM FRONT AND JUST EAST/NORTHEAST OF THE DRYLINE COULD CARRY AT
LEAST SOME BRIEF TORNADO POTENTIAL. SO MUCH DEPENDS ON THE EXACT
POSITION OF BOUNDARIES...POSSIBLE EFFECTS OF PREVIOUS
CONVECTION...ETC. AND ITS JUST TOO SOON TO SAY HOW THIS PLAYS OUT.

AS FOR OTHER POTENTIAL HAZARDS DURING THIS 6-DAY PERIOD...ANYTIME
THERE IS A SURFACE LOW IN THE REGION AS STRONG AS THE ONE SETTLING
IN THIS WEEKEND AND EVENTUALLY PASSING OFF TO THE EAST EARLY NEXT
WEEK...THERE IS USUALLY A PRETTY GOOD BET FOR AT LEAST ONE
ADVISORY-LEVEL WIND EVENT WITH SUSTAINED SPEEDS AROUND 30 MPH OR
HIGHER AND GUSTS TO AROUND 45 MPH. OF COURSE...MOST
MODELS/GUIDANCE DON/T START RAMPING UP WIND SPEEDS TO SOLIDLY
ADVISORY LEVELS UNTIL THE DAY 2-3 TIME FRAME AT THE EARLIEST...SO
AS A RESULT THE OFFICIAL FORECAST HAS ONLY A LIMITED COVERAGE OF
SPEEDS UP TO AROUND 30 MPH AT THIS TIME. HOWEVER...IT IS LIKELY
THAT OVER THE COMING DAYS SPEEDS WILL BE TRENDED UP EVEN MORE. AT
LEAST FOR NOW...THE HWO MENTIONS STRONG SOUTHERLY WIND POTENTIAL
MAINLY DURING THE SATURDAY NIGHT-SUNDAY TIME FRAME AND STRONG
NORTHWESTERLY WIND POTENTIAL FOR THE MONDAY-TUESDAY TIME FRAME.
LAST BUT NOT LEAST ON THE HAZARD FRONT...NOW THAT THE WEEKEND IS
TRENDING CONSIDERABLY WARMER THAN EXPECTED A FEW DAYS AGO...AT
LEAST NEAR-CRITICAL FIRE DANGER COULD ALSO COME INTO PLAY ON BOTH
SATURDAY/SUNDAY AFTERNOONS JUST BEHIND THE PROMINENT DRYLINE
EXPECTED TO SET UP IN/NEAR MAINLY SOUTHWEST PORTIONS OF THE CWA.
ALTHOUGH BOTH WINDS AND RELATIVE HUMIDITY VALUES SUPPORT NEAR-
CRITICAL TO CRITICAL THREAT...HAVE REFRAINED FROM AN HWO MENTION
OF FIRE DANGER AT THIS TIME DUE TO LINGERING UNCERTAINTIES ON
VEGETATIVE FUEL STATUS GIVEN THE RECENT...DECENT RAINFALL AND
SPRING GREEN-UP...AND WE MAY BE CHECKING WITH AREA FIRE MANAGERS
DURING THE NEXT FEW DAYS TO GET A BETTER IDEA OF HOW FIRE-PRONE WE
REALLY MIGHT BE. AS FOR POTENTIAL FROST-FREEZE CONCERNS...THE
7-DAY FORECAST REMAINS VOID OF ANY OBVIOUS ISSUES...AT LEAST FOR
NOW...AS EVEN THE COOLEST NIGHTS TUESDAY NIGHT AND WEDNESDAY NIGHT
WITH LOWS FORECAST INTO/NEAR THE UPPER 30S MAY HAVE TOO MUCH WIND
TO PROMOTE FROST FORMATION.

GETTING INTO SOME DETAILS IN GENERALLY 1-2 DAY BLOCKS...

FRIDAY NIGHT...CONFIDENCE REMAINS HIGH IN A DRY NIGHT...DESPITE
WEAK CONVECTIVE INSTABILITY RETURNING NORTHEASTWARD OVER THE AREA
ALONG A STRENGTHENING LOW LEVEL JET. THIS INSTABILITY APPEARS
CAPPED LOCALLY...WITH THE MAIN CONVECTIVE AREAS FAVORED TO BE WELL
NORTH ACROSS SD AND POSSIBLY ALSO INTO SOUTHEAST KANSAS. MADE
LITTLE CHANGE TO LOW TEMPS WITH LOWS UPPER 40S-MID 50S.

SATURDAY/SATURDAY NIGHT...AS ALREADY COVERED ABOVE...THERE IS A
BOATLOAD OF UNCERTAINTY WHETHER CONVECTION/POTENTIALLY SEVERE/
DEVELOPS OR NOT. IN THE MID-UPPER LEVELS...THERE IS GOOD AGREEMENT
BETWEEN THE ECMWF/GFS THAT THE POWERFUL VORT MAX IN THE BASE OF
THE PARENT 500 MILLIBAR TROUGH WILL MOVE FROM THE SOUTHERN CAL
AREA ON SATURDAY MORNING...TO NEAR THE CO/KS BORDER BY SUNRISE
SUNDAY...SWINGING OUT IN A NEGATIVELY TILTED FASHION. THE
ASSOCIATED STRENGTHENING SURFACE LOW WILL CRANK UP SOUTH-SOUTHEAST
WINDS LOCALLY...BUT WITH THE PRIMARY DRYLINE/INSTABILITY AXIS
LOOKING TO SET UP JUST SOUTH OF THE AREA...AND WITH LARGE SCALE
FORCING NOT OVERLY STRONG...THERE IS THE POTENTIAL FOR CAPPING TO
HOLD LOCAL CONVECTION AT BAY. IF STORMS DO FORM...AS THE GFS
SUGGESTS DURING THE EVENING...SEVER POTENTIAL IS CERTAINLY THERE
WITH 1500 J/KG CAPE IN THE PRESENCE OF AROUND 40KT OF DEEP-LAYER
SHEAR. TEMP-WISE SATURDAY...HIGHS WERE CHANGED LITTLE...BUT HAVE
SURE TRENDED UPWARD SINCE A FEW DAYS AGO...AIMED FROM UPPER 70S
NORTH TO MID-UPPER 80S SOUTH...AND THIS MAY NOT EVEN BE WARM
ENOUGH IN KS ZONES IF DRY AIR SURGES IN.

SUNDAY/SUNDAY NIGHT...AS ALREADY ALSO COVERED THE VERY
DYNAMIC...CLOSED MID LEVEL LOW MOVES NORTHEAST INTO
WESTERN/CENTRAL NEB IN SOME WAY...WITH THE ASSOCIATED SURFACE LOW
NEARBY. IN SOME WAYS...THIS COULD AT LEAST RESEMBLE A COLD-CORE
SEVERE WEATHER SETUP...AND AGAIN WILL REALLY HAVE TO WATCH THE
EVOLUTION OF THE LIKELY NORTHWEST-SOUTHEAST ORIENTED INSTABILITY
AXIS...THAT IS MOST FAVORED TO SET UP ACROSS THE NORTHERN HALF OF
THE CWA. CONFIDENCE ON HIGH TEMPS IS LOW...AS SOUTHERN/SOUTHWEST
AREAS ESPECIALLY COULD END UP QUITE A BIT WARMER THAN
FORECAST...BUT FOR NOW NUDGED UP MOST AREAS INTO THE 72-75 RANGE.
ALTHOUGH ANY SEVERE THREAT WOULD LIKELY END BY EVENING AS THE
INSTABILITY AXIS SHOOTS OFF TO THE NORTHEAST...HAVE LINGERED AT
LEAST AN ISOLATED AND POSSIBLY OVERDONE NON-SEVERE THUNDERSTORM
RISK INTO SUNDAY NIGHT.

MONDAY DAYTIME THROUGH TUESDAY NIGHT...THIS ENTIRE TIME FRAME
CONTINUES WITH A SMATTERING OF 20-50 POPS...WHICH SHOULD MAINLY BE
JUST RAIN SHOWERS WITH LITTLE TO NO CONVECTIVE INSTABILITY
EXPECTED. AS IT CURRENTLY STANDS...THE VERY SLOW MOVING MID-UPPER
LOW PRESSURE SYSTEM WILL WALLOW AROUND THE REGION AND EVEN BY
WEDNESDAY MORNING ONLY REACH A POSITION CENTERED OVER THE EASTERN
IA AREA. AS THE SURFACE LOW ALSO MOVES EAST...THE POTENTIAL FOR AT
LEAST ONE ROUND OF ADVISORY-LEVEL NORTHWEST WIND COMES INTO
PLAY...LIKELY FAVORING TUESDAY. TEMPS ON BOTH OF THESE DAYS
CHANGED LITTLE...WITH HIGHS GENERALLY AROUND 60 MONDAY AND
GENERALLY MID 50S TUES.

WEDNESDAY DAYTIME THROUGH THURSDAY...KEPT A SLIGHT CHANCE OF
SHOWERS GOING WEDNESDAY...BUT GIVEN THE PLETHORA OF POPS ALREADY
IN THE FORECAST DECIDED TO LEAVE WEDNESDAY NIGHT-THURSDAY VOID OF
PRECIP CHANCES AT LEAST FOR NOW...ALTHOUGH ITS NO GUARANTEE TO
STAY THAT WAY DEPENDING ON HOW SLOWLY THE SYSTEM DEPARTS ACROSS
THE UPPER MIDWEST/GREAT LAKES REGION. HIGH TEMPS PRELIMINARILY AIMED
ONLY INTO THE MID 50S-NEAR 60 EACH DAY...A TOUCH ON THE COOL SIDE
FOR THE OPENING OF MAY.

&&

.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1207 PM CDT THU APR 24 2014

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH DRY
CONDITIONS PREVAILING. SKIES WILL BE MAINLY CLEAR OR CLOUD COVER
WILL BE SCATTERED AT BEST. GUSTY NW WINDS THIS AFTERNOON WILL
DECREASE BY EVENING WITH WINDS BECOMING LIGHT/VARIABLE TONIGHT.
WINDS WILL TRANSITION SW ON FRIDAY.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR NEZ039-046-060-
     072-082.

KS...NONE.
&&

$$

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



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