Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 171205
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
705 AM CDT WED SEP 17 2014

.UPDATE...
ISSUED AT 705 AM CDT WED SEP 17 2014

SURE ENOUGH...LOCALLY DENSE FOG HAS GRADUALLY SHOWN ITS HAND
ACROSS MAINLY OUR NORTH CENTRAL KS ZONES...ALONG WITH PRIMARILY
OUR WESTERN-MOST COLUMN OF SOUTH CENTRAL NEBRASKA COUNTIES.
ALTHOUGH GROUND-TRUTH IS LIMITED...IT SEEMS THAT COUNTIES WITHIN
OUR CWA ARE MAINLY ON THE FRINGES OF MORE WIDESPREAD DENSE FOG
ISSUES MAINLY AFFECTING WESTERN NEB AND NORTHWEST KS. AS A
RESULT...HAVE OPTED AGAINST A FORMAL DENSE FOG ADVISORY AT THIS
TIME...BUT DID RECENTLY ISSUE A SPECIAL WEATHER STATEMENT TO
HEIGHTEN AWARENESS. IF CONDITIONS CONTINUE TO DETERIORATE THE
ONCOMING DAY SHIFT MAY HAVE TO CONSIDER A SHORT-FUSE ADVISORY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT WED SEP 17 2014

THE MAIN FORECAST ISSUES DURING THESE NEXT 24 HOURS CONSIST
OF...FIRSTLY: WHETHER OR NOT POTENTIALLY IMPACTFUL FOG WILL YET
DEVELOP THIS MORNING AND IF SO...WILL IT REMAIN MOSTLY HIT-AND-
MISS OR BECOME MORE WIDESPREAD IN SOME AREAS. SECONDLY: WILL AT
LEAST ISOLATED THUNDERSTORMS FLARE UP THIS EVENING AND ESPECIALLY
LATE TONIGHT...AND IF SO COULD A FEW EVEN BECOME STRONG TO
MARGINALLY SEVERE. THIRDLY: ALTHOUGH STEADIER SURFACE BREEZES
SHOULD ACT AGAINST FOG FORMATION A BIT MORE SO ON WEDNESDAY NIGHT
VERSUS THIS MORNING...AT LEAST PATCHY DEVELOPMENT AGAIN APPEARS
POSSIBLE AS LOW LEVEL MOISTURE AGAIN KICKS UP ANOTHER NOTCH.
TEMP-WISE...ASSUMING NO UNEXPECTED ENHANCED CLOUD ISSUES...BY FAR
THE BIG STORY IS THAT HIGHS TODAY ARE FORECAST TO BREACH THE 80+
MARK NEARLY CWA-WIDE...IN MANY PLACES FOR THE FIRST TIME IN 9
DAYS SINCE SEP. 8TH...A PRETTY NOTABLE STRETCH CONSIDERING MOST OF
IT OCCURRED DURING THE FIRST HALF OF SEPTEMBER.

STARTING WITH THE HERE AND NOW AS OF 0830Z/330 AM...OVERALL
ANOTHER VERY QUIET NIGHT ACROSS THE CWA...AS ANY WINDOW OF
OPPORTUNITY FOR ELEVATED CONVECTION IN SOUTHEAST ZONES HAS ALL
BUT PASSED BY...AS SEVERAL MODELS CORRECTLY SUGGESTED THAT THIS
ACTIVITY WOULD INITIATE AND FOCUS AT LEAST A FEW COUNTIES OUTSIDE
THE AREA OVER EASTERN KS/WESTERN MO AND THIS IN FACT HAS BEEN THE
CASE. MEANWHILE...11-3.9 MICRON SATELLITE IMAGERY REVEALS NEARLY
CLOUD-FREE SKIES OVER THE CWA...ALTHOUGH A RECENTLY FORMED RIBBON
OF LOW STRATUS RACING NORTH OUT OF CENTRAL KS TOWARD SOUTHEAST NEB
APPEARS POISED TO POSSIBLY BARELY BRUSH OUR EXTREME SOUTHEAST
ZONES AS IT TRACKS NORTH-NORTHEAST. AT THE SURFACE...A RATHER
DISORGANIZED VERY LIGHT/VARIABLE WIND REGIME IS IN PLACE OVER THE
CWA...AS THE LOCAL AREA LIES WELL TO THE WEST OF THE PRIMARY RIDGE
AXIS OVER THE IL/IN AREA...AND JUST TO THE NORTH OF A VERY WEAK
LOW AND TROUGH AXIS OVER SOUTHWEST KS. AS SUSPECTED 24 HOURS
AGO...THE COMBO OF MAINLY CLEAR SKIES/LIGHT BREEZES HAS FOSTERED
AT LEAST SOME LIMITED FOG DEVELOPMENT...BUT BASED ON AUTOMATED
AIRPORT OBS AT LEAST SO FAR ANY FOG HAS BEEN PRETTY HIT AND MISS
IN NATURE AND LIKELY FAVORING TYPICAL LOW LYING AREAS VERSUS MORE
WIDESPREAD. THAT BEING SAID...A FEW AUTOMATED WITHIN OR VERY NEAR
THE CWA HAVE AT LEAST BRIEFLY REPORTED VISIBILITY UNDER 1
MILE...INCLUDING A LOCALIZED QUARTER MILE AT ORD. AS FOR LOW TEMPS
THIS MORNING...PARTS OF ESPECIALLY THE NORTHWEST HALF OF THE CWA
ARE HEADING TOWARD LOWS A FEW DEGREES COOLER THAN EXPECTED AS A
FEW SPOTS HAVE EVEN DIPPED INTO THE UPPER 40S...WHILE MUCH OF THE
SOUTHEAST HALF OF THE CWA SHOULD BOTTOM OUT LOW-MID 50S AND EVEN
CLOSER TO 60 FAR SOUTH. IN THE MID-UPPER LEVEL PICTURE...WATER
VAPOR SATELLITE AND SHORT TERM MODEL DATA CONFIRM FAIRLY STEADY-
STATE NORTHWESTERLY FLOW OVER THE CENTRAL PLAINS...DIRECTED
BETWEEN A LARGE SCALE WESTERN CONUS RIDGE AND EASTERN CANADA
TROUGH. WELL TO THE SOUTHWEST...WEAKENING TROPICAL STORM ODILE IS
IN THE PROCESS OF SHIFTING OUT OF THE BAJA AREA TOWARD SOUTHERN
AZ. CLOSER TO HOME...A LOW AMPLITUDE DISTURBANCE ZIPPING SOUTHEAST
OVER THE NEB/IA/SD BORDER AREA TOWARD NORTHERN MO HAS HELPED
STRENGTHEN A WEST-SOUTHWESTERLY LOW LEVEL JET MAINLY OVER
KS...AND ITS NO COINCIDENCE THAT ITS EXIT REGION INTO THE KS/MO
BORDER REGION IS WHERE THE INCREASINGLY ACTIVE BAND OF MORNING
ELEVATED CONVECTION HAS FIRED UP.

LOOKING AHEAD AND NOW AND STARTING WITH THESE NEXT FEW HOURS
THROUGH AROUND SUNRISE...OBVIOUSLY FOG TRENDS ARE THE MAIN
CONCERN. ALTHOUGH FOG IS OFTEN A VERY FICKLE ENTITY...VERY SHORT
TERM VISIBILITY PROGS FROM THE RAP13 AND HRRR SUGGEST THAT THINGS
COULD CERTAINLY WORSEN/BECOME MORE WIDESPREAD YET THIS MORNING
PRIMARILY IN WESTERN AND SOUTHERN PORTIONS OF THE CWA...BUT MAYBE
ON A LOCALIZED BASIS ALMOST ANYWHERE. THINGS WOULD HAVE TO GET
CONSIDERABLE WORSE/WIDESPREAD TO EVEN BEGIN TO CONSIDER ANY KIND
OF FORMAL ADVISORY...BUT IT WILL LIKELY BE AT LEAST 14-15Z/9-10AM
BEFORE WE ARE COMPLETELY OUT OF THE WOODS ON SOME AREAS SEEING
VISIBILITIES NEAR/BELOW 1 MILE AND LOCALLY DENSE. THE BOTTOM LINE:
A MIX OF PATCHY FOG AND AREAS-OF FOG WORDING REMAINS IN THE
FORECAST FOR A FEW HOURS PAST SUNRISE...AND THESE TRENDS WILL BE
CLOSELY MONITORED.

GETTING BEYOND ANY MORNING FOG CONCERNS TO THE HEART OF THE
DAYTIME PERIOD...THE MAIN THEME HERE IS DRY CONDITIONS PERSISTING
IN THE PRESENCE OF NOTABLY WARMER CONDITIONS THAN OBSERVED LATELY.
IN THE MID-UPPER LEVELS...FAIRLY CONSISTENT AND LARGELY UNEVENTFUL
NORTHWESTERLY FLOW WILL CONTINUE OVER THE CENTRAL PLAINS AS THE
AFOREMENTIONED SUBTLE DISTURBANCE CURRENTLY JUST NORTHEAST OF THE
CWA DEPARTS WELL SOUTHEAST INTO THE OH VALLEY AREA BY DAYS END.
GIVEN THE LACK OF PERCEPTIBLE FORCING...CONFIDENCE IS RATHER HIGH
IN A DRY-DAY CWA-WIDE AS NEARLY ALL MODEL QPF AND REFLECTIVITY
FIELDS SUGGEST...AS ANY APPRECIABLE CONVECTIVE INSTABILITY THAT
MIGHT MANAGE TO BUILD SHOULD REMAIN CAPPED PER NAM FORECAST
SOUNDINGS. AT THE SURFACE...THE VERY LIGHT/VARIABLE BREEZES OF
THIS MORNING SHOULD GRADUALLY GIVE WAY TO PREVAILING EAST-
SOUTHEAST WINDS ONLY AROUND 10 MPH IN RESPONSE TO WEAK HIGH PLAINS
PRESSURE FALLS TO THE WEST. ONCE ANY MORNING LOWER STRATUS/FOG
THAT DEVELOPS BURNS OFF...SKIES SHOULD AVERAGE NO WORSE THAN
PARTLY CLOUDY DESPITE A FEW PASSING BATCHES OF MID-HIGH
CLOUDS...IN OTHER WORDS NO PESKY LOWER DAYTIME STRATUS DECK
ENVELOPING MUCH OF THE CWA DURING PEAK HEATING AS DID IN FACT
OCCUR YESTERDAY. THE OBVIOUS RESULT SHOULD BE A NOTICEABLE RISE
IN TEMPS VERSUS LATELY. THAT BEING SAID...DID NUDGE HIGHS DOWN
1-2 DEGREES FROM PREVIOUS FCST MAINLY ACROSS THE SOUTHERN CWA
WHILE LEAVING MUCH OF THE NORTH UNCHANGED. THE NET RESULT IS LOW
80S ACROSS MOST CENTRAL/NORTHEAST ZONES AND MAINLY MID 80S
SOUTHWEST WITH UPPER 80S MOST FAVORED IN FAR SOUTHWEST COUNTIES
SUCH AS ROOKS. THE AIRMASS WILL ALSO GET ANOTHER BOOST IN THE
HUMIDITY DEPARTMENT AS DEWPOINTS RISE INTO AT LEAST THE LOW 60S
MOST AREAS FOR THIS AFTERNOON.

TURNING TO THIS EVENING TONIGHT...THE BEST WAY TO DESCRIBE THINGS
IS THAT IT COULD BE A FAIRLY ACTIVE NIGHT IN PARTS OF THE CWA WITH
AT LEAST LIMITED STRONG THUNDERSTORM DEVELOPMENT AND AT LEAST
LIMITED FOG DEVELOPMENT...OR IT COULD ALMOST JUST AS EASILY BE
ANOTHER FAIRLY UNEVENTFUL NIGHT. SUCH IS THE FICKLE NATURE OF
NORTHWESTERLY-FLOW-ALOFT SITUATIONS WHEN LARGE-SCALE FORCING
REMAINS WEAK. SPEAKING OF THE MID-UPPER LEVELS...THE NORTHWESTERLY
FLOW PERSISTS BUT ACTUALLY MIGHT WEAKEN VERY SLIGHTLY AS THE MAIN
RIDGE AXIS ALIGNED OVER THE ROCKIES EDGES EVER SO SLIGHTLY FARTHER
EAST. THERE WILL UNDOUBTEDLY BE AT LEAST 1 OR 2 VERY LOW AMPLITUDE
DISTURBANCES WORKING SOUTHEASTWARD OVER/NEAR THE CWA TONIGHT...AND
COMPARED TO THIS MORNING THIS TIME AROUND IT APPEARS THERE WILL BE
MORE PRONOUNCED LOW-MID LEVEL CONVERGENCE OVER ESPECIALLY THE
SOUTHWESTERN 1/2 OF THE CWA TONIGHT AS NOTED IN 315K ISENTROPIC
SURFACE FORECASTS AND ALSO NOTED IN THE MORE WESTERLY FLOW AND
RESULTANT ELEVATED THETA-E ADVECTION BASED MAINLY IN THE 800-700MB
LAYER. PER VARIOUS DETERMINISTIC AND HIGHER-RES REFLECTIVITY MODEL
SOLUTIONS...AT LEAST A FEW THUNDERSTORMS ARE EXPECTED TO FLARE UP
ALONG THIS ELEVATED CONVERGENCE ZONE...WITH THE GREATEST
LIKELIHOOD WITHIN THE SOUTHWESTERN 1/2 OF THE CWA AFTER MIDNIGHT.
THAT BEING SAID...STORMS CANNOT BE COMPLETELY BE RULED OUT BEFORE
MIDNIGHT EITHER AND HAVE MAINTAINED SOME 20 POPS IN SOUTHWESTERN
AREAS DURING THE EVENING WHILE EXPANDING AT LEAST 20 POPS TO ALL
AREAS AFTER MIDNIGHT BUT FOCUSING HIGHEST 30S IN SOUTHERN ZONES.
SHOULD CONVECTION MATERIALIZE...CERTAINLY A FEW STRONG STORMS
CAPABLE OF PRODUCING HAIL TO AT LEAST NICKEL SIZE OR SLIGHTLY
LARGER CANNOT BE RULED OUT GIVEN ELEVATED CAPE OF 1000-1500 J/KG
IN THE PRESENCE OF AROUND 40KT OF DEEP LAYER SHEAR. MEANWHILE AT
THE SURFACE...FAIRLY LIGHT BUT STEADY EASTERLY BREEZES GENERALLY
5-10 MPH SHOULD PERSIST OVERNIGHT...WHICH SHOULD HELP WORK AGAINST
ANY WIDESPREAD/IMPACTFUL FOG FORMATION...ALONG WITH OF COURSE ANY
LOCALIZED MIXING FROM CONVECTIVE ACTIVITY. THAT BEING SAID...AT
LEAST PATCHY LIGHT FOG CERTAINLY CANNOT BE RULED OUT IN THE MOIST
EASTERLY FLOW...SO HAVE INTRODUCED PATCHY FOG TO THE LATE NIGHT
FORECAST. THE EARLIER 00Z NAM SUGGESTED THAT POTENTIALLY
WIDESPREAD LOW STRATUS AND POSSIBLE LIGHT DRIZZLE COULD
MATERIALIZE AS WELL...BUT THE LATEST 06Z NAM SUGGESTS THAT LOW
LEVEL MOISTURE DEPTH WILL LIKELY REMAIN INSUFFICIENT FOR DRIZZLE
PRODUCTION. MADE VERY LITTLE ALTERATION TO LOW TEMPERATURES...AS
ANOTHER UPWARD CLIMB FROM ONE NIGHT TO THE NEXT CONTINUES...WITH
LOWS AIMED FROM THE UPPER 50S NORTH...LOW 60S CENTRAL AND MID 60S
SOUTH.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 445 AM CDT WED SEP 17 2014

SUMMARY...FRIDAY...WITH HIGHS IN THE MID 80S...STILL APPEARS TO THE
BE THE WARMEST DAY OF THE NEXT 7 DAYS FOR MOST AREAS...ALTHOUGH IT
WILL NOT BE ALL THAT MUCH WARMER THAN TODAY. RAIN CHANCES IN THE
EXTENDED PERIOD ARE NOT THAT GOOD AND CHANCES HAVE EVEN FALLEN OFF A
LITTLE BIT DURING THE PERIODS WHERE 24HRS EARLIER THEY LOOKING THE
BEST...FRIDAY NIGHT INTO SATURDAY. OVERALL IT WILL BE A FAIRLY
TYPICAL MID SEPTEMBER PERIOD WITH HIGHS ON MOST DAYS AVERAGING OUT
IN THE 70S TO AROUND 80.

THURSDAY...THE UPPER RIDGE OVER THE ROCKIES WILL SLIDE FURTHER EAST
INTO THE PLAINS AND PRECIPITATION CHANCES SHOULD DECREASE. THERE IS
WEAK ISENTROPIC LIFT IN THE LOWEST LAYER FROM AROUND AND BELOW 850
MB AND FORECAST MODELS INDICATE THAT A LOW STRATUS DECK COULD
PERSIST THROUGH MUCH OF THE DAY. INITIALLY THIS STRATUS DECK MAY BE
LOW ENOUGH TO BE FOG RIGHT AFTER SUNRISE. SOME FORECAST MODELS ARE
TRYING TO GENERATE A HUNDREDTH OR TWO OF SPLOTCHY QPF. TYPICALLY
THIS COULD BE SPRINKLES...DRIZZLE...OR EVEN ISOLATED THUNDERSTORMS.
IN THIS CASE THE FORECAST SOUNDINGS INDICATE THAT THE SATURATED
STRATUS DECK WILL BE BELOW 850 MB AND NOT THICK ENOUGH TO PRODUCE
DRIZZLE. THERE COULD BE SOME CLOUD SEEDING FROM PASSING MID CLOUDS
GENERATING A FEW SPRINKLES...BUT MOST AREAS WILL BE DRY. THERE IS
SOME WEAK INSTABILITY SO WE CAN NOT RULE OUT THUNDERSTORMS...BUT
ODDS OF THUNDER ARE LOW ENOUGH TO CONTINUE TO KEEP IT OUT OF THE
FORECAST FOR NOW. THE STRATUS DECK WILL KEEP TEMPERATURES DOWN
ESPECIALLY ACROSS NEBRASKA ZONES WHERE STRATUS WILL LIKELY LINGER
LONGER. HIGHS WILL RANGE FROM THE MID 70S IN THE TRI CITIES TO THE
MID 80S ACROSS OUR SOUTHWEST KANSAS COUNTIES.

THURSDAY NIGHT INTO FRIDAY AFTERNOON...THERE IS GOOD AGREEMENT IN
NUMEROUS FORECAST MODELS AND MODEL BLENDS THAT THIS WILL BE A DRY
PERIOD ACROSS OUR FORECAST AREA. THE REMNANTS OF HURRICANE ODILE WILL
BE HEADING NORTHEAST INTO THE TEXAS PANHANDLE AND POSSIBLY INTO FAR
SOUTHWEST KANSAS BY FRIDAY AFTERNOON...BUT STILL OUTSIDE OF OUR
FORECAST AREA. AN UPPER TROUGH COMING OUT OF THE NORTHERN STREAM
WILL BE BREAKING OFF A VORT MAX OVER CALIFORNIA RESULTING IN A LESS
VIGOROUS WAVE FOR OUR FORECAST AREA THAN WAS INDICATED IN MODEL RUNS
24HRS AGO.

FRIDAY NIGHT INTO SATURDAY...THE UPPER TROUGH SWINGING THROUGH THE
PLAINS IS LOOKING LESS IMPRESSIVE WITH RECENT FORECAST RUNS AS SOME
OF THE ENERGY IS BEING LEFT BEHIND OVER CALIFORNIA WHERE IT LEAVES
BEHIND A CUT OFF LOW. MODEL BLENDS HAVE REDUCED POPS SOME IN THIS
PERIOD...AND IT SEEMS JUSTIFIED GIVEN THE SYNOPTIC SITUATION. WILL
HAVE TO REALLY KEEP AN EYE ON THE REMNANTS OF ODILE DURING THIS
PERIOD AS THE REMAINING VORT MAX AND MOISTURE WILL BE COMING UP
THROUGH KANSAS AND MIGHT BE FAR ENOUGH NORTH TO IMPACT OUR CWA.
HOWEVER...THE BETTER BET AT THIS TIME FOR ODILE RELATED
MOISTURE/RAINFALL WILL BE JUST TO THE SOUTH OF OUR FORECAST AREA.

SUNDAY THROUGH TUESDAY...UPPER LEVEL RIDGING WILL RESUME ACROSS THE
WESTERN CONUS WITH GENERALLY DRY WEATHER LIKELY FOR OUR FORECAST
AREA. CAN NOT COMPLETELY RULE OUT A SHORT WAVE SLIDING DOWN INTO OUR
FORECAST AREA ON THE EAST SIDE OF THE RIDGE BY TUESDAY...BUT MOST
AREAS APPEAR DRY AT THIS TIME. HIGH TEMPERATURES WILL BE NEAR NORMAL
AVERAGING OUT IN THE 70S.

&&

.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH THURSDAY MORNING)
ISSUED AT 700 AM CDT WED SEP 17 2014

ALTHOUGH CONFIDENCE IS FAIRLY HIGH IN VFR CEILING/VISIBILITY
THROUGH THE MIDDLE 12-18 HOURS OF THE VALID PERIOD...THERE IS
QUITE A BIT UNCERTAINTY REGARDING BOTH THE INITIAL FEW HOURS RIGHT
AWAY THIS MORNING...AND THEN AGAIN LATE TONIGHT. IN
ADDITION...THERE IS AT LEAST A LOW RISK FOR SHOWERS/THUNDERSTORMS
AT ONE OR BOTH TERMINALS ESPECIALLY DURING THE OVERNIGHT
HOURS...BUT CONFIDENCE IN OCCURRENCE IS STILL TOO LOW AT THIS TIME
RANGE TO EVEN JUSTIFY A VICINITY THUNDERSTORM (VCTS). STARTING
WITH THE FIRST FEW HOURS THIS MORNING...THERE IS STILL A CHANCE
THAT AT LEAST LIGHT FOG AND OR BRIEF LOW STRATUS COULD MOVE INTO
THE AREA...BUT IT HAS REMAINED AT LEAST SLIGHTLY WEST AND/OR SOUTH
OF THE AREA THUS FAR. GIVEN CONSIDERABLE UNCERTAINTY...WILL RUN A
TEMPO GROUP FOR MVFR VISIBILITY WITH AMENDMENTS VERY POSSIBLE.
ONCE ANY MORNING FOG/STRATUS BURNS...SEVERAL HOURS OF
HIGH-CONFIDENCE VFR COMMENCES. THEN LATE TONIGHT...MOIST EASTERLY
FLOW COULD SPARK ANOTHER ROUND OF STRATUS AND FOG...AND HAVE
INTRODUCED MVFR CATEGORIES IN EACH STARTING AT 08Z. SURFACE
BREEZES SHOULD NOT BE MUCH OF AN ISSUE THROUGH THE PERIOD...WITH
SUSTAINED SPEEDS AVERAGING UNDER 10KT AND FROM AN EAST-SOUTHEAST
DIRECTION THROUGH MOST OF THE PERIOD.

&&

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

$$

UPDATE...PFANNKUCH
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...PFANNKUCH


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