Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 231845
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
145 PM CDT THU OCT 23 2014

.UPDATE...
ISSUED AT 127 PM CDT THU OCT 23 2014

UPDATED THE FORECAST EARLIER TO EXPIRE THE DENSE FOG ADVISORY THAT
WAS EXTENDED IN TIME AGAIN. HOWEVER...THERE ARE STILL POCKETS OF
DENSE FOG STUBBORNLY CLINGING THROUGH MID-AFTERNOON. THERE IS ALSO
AN ASSOCIATED AREA OF STRATUS VERY SLOWLY ERODING TODAY...MAKING
THE TEMPERATURE FORECAST DIFFICULT.

UPDATE ISSUED AT 634 AM CDT THU OCT 23
2014

WELL...SO MUCH FOR POSSIBLY BEING ABLE TO KEEP A HANDFUL OF OUR
EASTERN/SOUTHEASTERN-MOST COUNTIES OUT OF THE DENSE FOG ADVISORY.
MAINLY OVER THE PAST 60-90 MINUTES...SEVERAL AREAS DOWN HIGHWAY
81 FROM YORK-HEBRON AND DOWN INTO JEWELL/MITCHELL COUNTIES IN KS
HAVE STARTED TO TANK DOWN TO AROUND 1/4 MILE OR LESS PER AUTOMATED
OBS AND SEVERAL PHONE CALLS. THIS REALLY SHOULDN/T BE A SURPRISE
AS EVEN THOUGH THIS PARTICULAR AREA WAS NOT WELL-CAPTURED BY THE
HRRR/RAP13 VISIBILITY PROGS...THE AMBIENT CONDITIONS ARE VERY
SIMILAR TO THE REMAINDER OF THE CWA AND AS THE BOUNDARY LAYER
COOLED FOG READILY FORMED THERE AS WELL. ON A SIDE NOTE...ALTHOUGH
DENSE FOG IS OBVIOUSLY NOT ALL THAT UNCOMMON AROUND HERE...ITS
NOT EVERYDAY THAT LITERALLY ALL 13 PRIMARY AUTOMATED AIRPORT
ASOS/AWOS SITES WITHIN OUR CWA (ALONG WITH SEVERAL SITES JUST
OUTSIDE OUR CWA) REPORT VISIBILITY OF ONE-QUARTER MILE OR LESS AT
THE SAME TIME.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT THU OCT 23 2014

ALTHOUGH CONFIDENCE IS RATHER HIGH IN A DRY 24 HOURS...THE MAIN
FORECAST ISSUE HAS NOW TURNED TO WIDESPREAD FOG FOR THIS
MORNING (MUCH OF WHICH IS DENSE)...AND THERE ARE PLENTY OF
QUESTIONS REGARDING JUST HOW LONG THIS FOG AND/OR LOW STRATUS WILL
LAST AND HOW MUCH EFFECT IT MIGHT HAVE ON AFTERNOON HIGH TEMPS.
ALTHOUGH ITS NOT OUT OF THE QUESTION THAT A MORE LIMITED/PATCHY
ROUND OF FOG COULD AGAIN MATERIALIZE FOR THURSDAY NIGHT...HAVE
OPTED AGAINST FORECAST INCLUSION AT THIS TIME GIVEN THAT THE LOW-
LEVEL ENVIRONMENT SHOULD BE CONSIDERABLY MORE MIXED AND
INHOSPITABLE TO WIDESPREAD ISSUES.

STARTING WITH THE CURRENT SCENE AS OF 09Z/4AM...ALTHOUGH THE
POSSIBILITY OF IMPACTFUL FOG WAS RECOGNIZED HERE 24 HOURS
AGO...KUDOS TO PREVIOUS DAY SHIFT FOR HITTING THE THROTTLE HARDER
WITH IT...AS A LARGE PERCENTAGE OF THE CWA IS CURRENTLY
EXPERIENCING VISIBILITIES AROUND/LESS THAN 1/4 MILE PER AUTOMATED
AIRPORT OBS AND HIGHWAY CAMS...AND A DENSE FOG ADVISORY IS OUT FOR
THE MAJORITY OF THE CWA THROUGH 16Z/11AM. AT LEAST SO
FAR...MAINLY ONLY THE FAR EASTERN COUNTIES FROM YORK-HEBRON-
BELOIT SEEM TO BE MISSING OUT ON WIDESPREAD DENSE FOG
ISSUES...LIKELY IN PART TO HOLDING UP A BIT WARMER IN THE WAKE OF
THE DEPARTING CLOUD SHIELD FROM YESTERDAY/S LOW PRESSURE SYSTEM.
ALTHOUGH THIS COULD EASILY CHANGE OVER THE NEXT FEW
HOURS...SHORT-TERM MODELED VISIBILITY FROM THE LATEST RAP13/HRRR
SUGGEST WE MAY GET AWAY WITHOUT NEEDING TO EXPAND THE ADVISORY
AGAIN...TIME WILL TELL. OBVIOUSLY TWO OF THE BIGGEST FACTORS IN
FOG FORMATION WERE FRESHLY WET GROUND FROM WIDESPREAD RAIN
YESTERDAY (WHICH NEARED OR EXCEEDED 1 INCH IN A BIT MORE OF THE
AREA THAN EXPECTED) AND VERY LIGHT TO NEAR-CALM BREEZES ALONG THE
AXIS OF A WEAK COLD FRONT THAT HAS ESSENTIALLY WASHED OUT ACROSS
THE CWA IN A SOUTHWEST-TO-NORTHEAST FASHION. LOW TEMPS THIS
MORNING APPEAR TO BE WORKING OUT FAIRLY WELL...WITH A DECENT RANGE
FROM LOW-MID 40S NORTHWEST TO LOW-MID 50S SOUTHEAST. IN THE BIG
PICTURE OF THE MID-UPPER LEVELS...WATER VAPOR IMAGERY AND SHORT
TERM MODEL DATA CONFIRMS THAT THE CWA IS NOW JUST BEHIND THE
DEPARTING SHORTWAVE TROUGH AXIS THAT BROUGHT YESTERDAY/S
RAIN...WITH THIS AXIS GENERALLY ALIGNED ALONG THE MO RIVER VALLEY.

LOOKING AHEAD FORECAST-WISE...NEEDLESS TO SAY THE NUMBER ONE ISSUE
AND QUESTION IS HOW LONG DOES DENSE FOG LINGER...AND COULD LOW
STRATUS STICK AROUND LONG ENOUGH TO HAMPER HIGH TEMPS ESPECIALLY
IN THE EASTERN CWA.

BASED ON THE USUALLY FAIRLY-RELIABLE SHORT TERM MODELED VISIBILITY
FROM THE HRRR/RAP13...IT MAY BE WELL INTO THE MID-LATE MORNING
HOURS BEFORE AN APPRECIABLE PERCENTAGE OF THE CWA SHAKES FREE OF
WIDESPREAD FOG ISSUES. AS A RESULT...OPTED TO EXTEND THE ADVISORY
TIME AN HOUR OR TWO LONGER THAN "USUAL" TO 16Z/11AM...AS WOULD
RATHER HAVE DAY SHIFT BE ABLE TO CANCEL SOME COUNTIES EARLY THAN
HAVE TO ISSUE EXTENSIONS. ALTHOUGH MUCH OF THIS FOG IS LIKELY
FAIRLY SHALLOW...THE LOW-LEVEL ENVIRONMENT WILL LIKELY NOT SUPPORT
A RAPID FOG DISSIPATION GIVEN APPRECIABLE BOUNDARY LAYER
SATURATION AND ONLY VERY WEAK MIXING AS A BROAD SURFACE RIDGE AXIS
MIGRATES THROUGH THE AREA AND KEEPS BREEZES VERY LIGHT. EVENTUALLY
AS THE AFTERNOON WEARS ON...A STEADIER 5-10 MPH SOUTHERLY BREEZE
WILL KICK IN...IN RESPONSE TO SUBTLE PRESSURE FALLS TO THE WEST
AND NORTHWEST. ALTHOUGH THESE SORT OF SITUATIONS MAKE FOR VERY
TRICKY SKY COVER/TEMPERATURE FORECASTS...THE GENERAL EXPECTATION
IS FOR PLENTY OF FOG/LOW CLOUDS THIS MORNING TO GRADUALLY GIVE WAY
TO NO-WORSE-THAN PARTLY CLOUDY SKIES THIS AFTERNOON...ALTHOUGH
THE EARLIEST CLEARING MIGHT VERY WELL TARGET THE WESTERN CWA FIRST
AND PORTIONS OF THE CENTRAL/EAST LAST. ADDING TO THE TEMPERATURE
UNCERTAINTY IS A NOTABLE 10-ISH DEGREE SPREAD BETWEEN NAM MET
(COOLER) AND GFS MAV (WARMER) NUMERICAL GUIDANCE TODAY. IF
ANYTHING...HAVE PROBABLY AIMED FORECAST HIGHS A TOUCH ON THE
PESSIMISTIC SIDE BY LOWERING 2-3 DEGREES FROM PREVIOUS FORECAST
ACROSS MUCH OF THE CWA...BUT FOR NOW WILL RUN WITH UPPER 60S TO
NEAR 70 ACROSS MUCH OF THE CENTRAL/EAST AND MORE IN THE WAY OF
MID-70S FAR WEST. THERE COULD BE AT LEAST SOME MODEST COVERAGE OF
HIGH CIRRUS THIS AFTERNOON AS SOME HIGH CLOUDS SPILL EAST-
SOUTHEAST INTO THE AREA IN ASSOCIATION WITH A FAIRLY LOW AMPLITUDE
DISTURBANCE TRACKING MAINLY FROM THE NORTHERN ROCKIES INTO THE
DAKOTAS.

FOR THIS EVENING/TONIGHT...AFOREMENTIONED FAIRLY WEAK
DISTURBANCES JUST TO THE NORTHWEST OF THE LOCAL AREA WILL SLIDE
EAST-SOUTHEAST OVER THE CENTRAL PLAINS...RIDING AROUND THE EDGE OF
A BROAD MID-UPPER RIDGE EDGING NORTH-NORTHEAST OUT OF THE DESERT
SOUTHWEST. AS A WEAK LOW PRESSURE AXIS EXTENDING SOUTHWARD INTO
THE CENTRAL PLAINS OUT OF THE DAKOTAS/CANADA BRUSHES THROUGH THE
REGION TONIGHT...THE LOW LEVEL ENVIRONMENT SHOULD BE CONSIDERABLY
MORE INHOSPITABLE TO IMPACTFUL FOG FORMATION AS SOUTH-
SOUTHWESTERLY BREEZES BECOME FAIRLY STEADY AT 5-10 MPH AND LOCALLY
HIGHER. THAT BEING SAID...NEXT FEW SHIFTS WILL WANT TO KEEP AN EYE
ON AT LEAST LIMITED/PATCHY FOG POTENTIAL AS SOMEWHAT STRANGELY THE
06Z NAM VISIBILITY PRODUCT IS HITTING PARTS OF THE CWA HARDER THAN
SEEMS JUSTIFIED LATE TONIGHT. THANKS MAINLY TO THE STEADIER
SOUTHERLY BREEZES AND AT LEAST SOME DEGREE OF PASSING HIGH CLOUD
COVER...A SEASONABLY MILD NIGHT IS IN STORE AND NUDGED LOW TEMPS
GENERALLY 1-2 DEGREES UPWARD FROM PREVIOUS FORECAST IN MOST
AREAS...KEEPING MOST OF THE CWA UP IN THE LOW-MID 50S EXCEPT A
GREATER LIKELIHOOD OF SOME 40S IN FAR WESTERN/NORTHERN COUNTIES.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 445 AM CDT THU OCT 23 2014

ABOVE NORMAL TEMPERATURES AND DRY WEATHER WILL BE THE RULE THROUGH
THE MAJORITY OF THE PERIOD.

THE FORECAST PATTERN SUGGESTS A LONG WAVE TROUGH WILL MOVE INLAND
OFF THE WEST COAST LATE IN THE WEEKEND. THE TROUGH IS FORECAST TO
PROGRESS ACROSS THE AREA AND EXIT TO THE EAST BY TUESDAY. OTHERWISE
BENIGN WEATHER IS EXPECTED TO CONTINUE AS A ZONAL PATTERN PERSISTS.

SO...SPECIFICALLY...WE EXPECT MUCH ABOVE NORMAL TEMPERATURES FRIDAY
THROUGH MONDAY...THEN A COOL FRONT IS EXPECTED TO MOVE THROUGH BY
MONDAY AFTERNOON. A FEW SHOWERS ARE HARD TO COMPLETELY RULE OUT IN
THE VICINITY OF THE FRONT. CURRENTLY IT APPEARS ANY RAIN THAT OCCURS
MONDAY THROUGH MONDAY EVENING WOULD BE VERY LIGHT AND MOST LIKELY
SPRINKLES AT BEST. NEAR NORMAL TEMPERATURES ARE EXPECTED TUESDAY AND
WEDNESDAY WITH DRY CONDITIONS CONTINUING.

FRIDAY AFTERNOON PRESENTS A CONCERN IN TERMS OF FIRE WEATHER. THE
AREA IS FORECAST TO SEE RELATIVE HUMIDITIES DROP BELOW 25% THROUGH
THE AFTERNOON HOURS...BUT CURRENTLY WINDS ARE EXPECTED TO BE 15 MPH
OR LESS. SO...CURRENT FORECAST CONDITIONS DO NOT WARRANT A MENTION
OF ANY FIRE DANGER AT THIS POINT...BUT WE WILL CONTINUE TO
MONITOR.

&&

.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1247 PM CDT THU OCT 23 2014

CONFIDENCE IS LOW REGARDING VISIBILITY AND ESPECIALLY CEILING.
MODELS ARE NOT DOING THAT WELL WITH EITHER. BASED LARGELY ON
PATTERN RECOGNITION...VISIBILITY SHOULD BE ON THE WAY UP THIS
AFTERNOON...BUT CEILINGS MAY STRUGGLE TO SCATTER. SINCE THERE WILL
BE NO APPRECIABLE AIRMASS CHANGE...STRATUS WILL LIKELY
RETURN...IF IT DOES MANAGE TO SCATTER...WITH THE POSSIBILITY OF
REDUCED VISIBILITY. IT IS A TOUGH CALL FOR CEILING HEIGHT AND HOW
LOW VISIBILITY WILL DROP...BUT THERE IS POTENTIAL FOR MORE DENSE
FOG AND CEILINGS IN THE LIFR/IFR CATEGORY...MUCH LIKE WE HAD LAST
NIGHT AND TODAY.

&&

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

$$

UPDATE...HEINLEIN
SHORT TERM...PFANNKUCH
LONG TERM...EDDY
AVIATION...HEINLEIN



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