Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 122202
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
502 PM CDT SAT APR 12 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 502 PM CDT SAT APR 12 2014

NEEDLESS TO SAY...THIS IS A VERY COMPLEX AND LOW-CONFIDENCE 24
UPCOMING 24 HOURS...ESPECIALLY WITH REGARDS TO SHOWER/THUNDERSTORM
CHANCES AND POTENTIAL RAIN AMOUNTS...NOT TO MENTION THE POSSIBLE
TRANSITION TO AT LEAST A RAIN/SNOW MIX THAT COULD TAKE PLACE
WITHIN MAINLY THE NORTHWESTERN 1/3 OF THE CWA ON SUNDAY AFTERNOON.
OF HIGHER CONFIDENCE IS THAT NORTH WINDS WILL BE FAIRLY STRONG ON
SUNDAY ESPECIALLY BETWEEN THE MID-MORNING AND EARLY EVENING
HOURS. ALTHOUGH SUSTAINED SPEEDS COULD BE A BIT MARGINAL FOR
MEETING ADVISORY CRITERIA OF 30+ MPH THE ENTIRE TIME...OPTED TO GO
AHEAD AND ISSUE A CWA-WIDE WIND ADVISORY VALID FROM 9AM-
7PM...ALTHOUGH ITS CERTAINLY POSSIBLE THAT THE UPCOMING NIGHT
SHIFT COULD MAKE SOME MINOR TWEAKS TO THE START AND/OR END TIMES
BASED ON THE LATEST DATA.

STARTING WITH THE HERE AND NOW...THE CWA REMAINS SHOWER/STORM FREE
UNDER A CONSIDERABLE AMOUNT OF MID-HIGH CLOUDS AT THIS TIME...AS
HIGH TEMPS ARE LOOKING TO TOP OUT 76-81 ACROSS MOST OF THE AREA.
AT THE SURFACE...A FAIRLY WEAK COLD FRONT THAT IS ACTUALLY SERVING
AS MORE OF A DRYLINE THAN ANYTHING HAS MADE IT THROUGH ROUGHLY THE
NORTHWEST TWO-THIRDS OF THE CWA...WHERE WINDS HAVE TAKEN ON SOME
KIND OF NORTHERLY COMPONENT...WHILE MUCH OF THE SOUTHEAST 1/3 IS
EXPERIENCING MORE OF A LIGHT/VARIABLE OR SOUTHWESTERLY COMPONENT.
THIS BOUNDARY HAS DROPPED DEWPOINTS WELL DOWN INTO THE 30S IN FAR
WEST- CENTRAL/NORTHWEST COUNTIES...AND AS A RESULT LIMITED AREAS
WILL FLIRT WITH NEAR-CRITICAL FIRE DANGER FOR A FEW MORE HOURS
BEFORE EVENING COOLING SETS IN. HOWEVER...THE MAJORITY OF THE CWA
IS STILL SITTING WITH DEWPOINTS WELL INTO THE 40S TO AROUND
50...ALTHOUGH THESE VALUES HAVE ALSO MIXED DOWNWARD SINCE EARLIER
THIS MORNING. ALOFT...GENERALLY WESTERLY FLOW IS IN PLACE...WITH
THE CWA DOWNSTREAM FROM TWO MAIN DISTURBANCES...A NORTHERN STREAM
SHORTWAVE TROUGH HEADING SOUTHEAST THROUGH THE NORTHERN
ROCKIES...AND A SOUTHERN STREAM TROUGH HEADING EAST ACROSS AZ
TOWARD NM.

FOR LATE THIS AFTERNOON THROUGH TONIGHT...THE NUMBER ONE MESSAGE
WE NEED TO CONVEY HERE IS THAT SHOWER/THUNDERSTORM CHANCES DO NOT
APPEAR AS LIKELY AS THEY DID 12-24 HOURS AGO...ESPECIALLY THROUGH
THE EVENING AND EARLY OVERNIGHT HOURS...WITH MAYBE SOMEWHAT BETTER
CHANCES GETTING GOING CLOSER TO SUNRISE. AS A RESULT...HAVE PULLED
POPS FOR MUCH OF THE NORTHERN TWO-THIRDS OF THE CWA PRIOR TO
MIDNIGHT...AND EVEN AFTER MIDNIGHT HAVE NO HIGHER THAN 50-50
CHANCES. TO MAKE A LONG STORY SHORT...FORECAST SOUNDINGS AND
CURRENT OBJECTIVE ANALYSIS REVEALS A STRONG CAP IN PLACE FOR
NEAR-SURFACE BASED THUNDERSTORM DEVELOPMENT...DESPITE THE PRESENCE
OF 1000-1500 J/KG MIXED LAYER CAPE ACROSS MUCH OF THE
SOUTHERN/EASTERN CWA. THIS CAP IS A BIT WEAKER TO THE EAST...AND
VARIOUS MODELS STRONGLY SUGGEST THAT THE VAST MAJORITY OF
CONVECTION THROUGH THIS EVENING WILL FOCUS ALONG AN AXIS FROM IA
INTO NORTHEAST KS...AND AT LEAST BARELY MISS THE CWA. AS A
RESULT...MOST OF THE LOCAL AREA WILL LIKELY END UP WAITING UNTIL
LATER TONIGHT IF NOT MORE SO SUNDAY MORNING FOR INCREASING UPPER
FORCING/COOLING ALOFT AND INCREASING CONVERGENCE IN THE 850-700MB
LAYER TO INITIATE SHOWERS/STORMS. WHEN AND IF STORMS DO FORM
TONIGHT...THE MAIN SEVERE THREAT WILL LIKELY BE HAIL UP TO AROUND
THE SIZE OF QUARTERS...AND PRIMARILY SOUTH OF A YORK-ALMA LINE
INCLUDING KS ZONES. CERTAINLY WITH DEEP LAYER SHEAR ON THE ORDER
OF 50-60 KT...AT LEAST SOME BRIEF ELEVATED SUPERCELL
CHARACTERISTICS ARE POSSIBLE.

FOR SUNDAY DAYTIME...THE MAIN STORY IS THAT PRECIP CHANCES
INCREASE CONSIDERABLY AS THE HEART OF THE LEADING SHORTWAVE TROUGH
ASSOCIATED WITH THE SOUTHERN STREAM SYSTEM PASSES DIRECTLY OVER
THE AREA...GREATLY INCREASING MID-LEVEL CONVERGENCE/SATURATION.
WITH THE 18Z NAM INDICATING THAT ELEVATED MUCAPE WILL STILL BE
WELL INTO AT LEAST THE 500-1000 J/KG RANGE ACROSS MUCH OF THE
SOUTHERN CWA ON SUNDAY MORNING...THERE COULD EASILY BE A CONTINUED
RISK OF MARGINALLY SEVERE STORMS WITH A HAIL THREAT WELL INTO THE
MID-DAY HOURS BEFORE INSTABILITY FADES AWAY SOUTHWARD WITH TIME.
WHETHER STORMS ARE STRONG/SEVERE OR NOT...A FAIRLY WIDESPREAD AREA
OF RAIN SHOWERS SHOULD BLOSSOM DURING THE DAY...AND POPS IN NEARLY
ALL AREAS ARE ADVERTISED IN THE 70-90 RANGE FOR AT LEAST PART OF
THE DAY. AS COLDER AIR COMES IN FROM THE NORTHWEST...WE SHOULD SEE
AT LEAST A RAIN/SNOW MIX DEVELOP IN PRIMARILY THE NORTHWEST 1/3 OF
THE CWA IN THE AFTERNOON...BUT HAVE CONTINUED TO KEEP ANY GROUND
ACCUMULATION UNDER ONE-HALF INCH AS THE ANTECEDENT WARM AND LIKELY
WET GROUND SHOULD WORK AGAINST MUCH IN THE WAY OF IMPACTFUL SNOW.
THIS DOES BEAR WATCHING THOUGH FOR ANY LAST MINUTE SURPRISES. AT
THE SURFFACE...STRONG PRESSURE RISES WILL BUILD ACROSS THE AREA TO
THE NORTH OF THE PRIMARY SURFACE LOW MOVING EASTWARD ACROSS
SOUTHERN/EASTERN KS...AND CONFIDENCE IS FAIRLY HIGH THAT MUCH OF
THE CWA SHOULD AT LEAST BRIEFLY VERIFY THE AFOREMENTIONED WIND
ADVISORY.

OFFICIALLY...BOTH LOW TEMPS TONIGHT AND HIGHS SUNDAY WILL BE
ALMOST IDENTICAL...RANGING FROM MID 40S NORTHWEST TO MID-UPPER 50S
SOUTHEAST. HOWEVER...PLEASE KEEP IN MIND THAT TEMPS WILL BE ON A
STEADY...COLD FALL DURING THE DAYTIME HOURS WITH HIGHS REACHED
VERY EARLY ON. AS A RESULT...MID-AFTERNOON READINGS ARE ONLY
PROGGED TO BE SOMEWHERE IN THE MID-30S TO LOW-40S RANGE ACROSS
MOST OF THE CWA...COMBINING WITH THE WINDS AND PRECIP FOR A RATHER
RAW DAY.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 502 PM CDT SAT APR 12 2014

FORECAST FOCUS ON THE CHANCES OF PRECIPITATION ON AND OFF THROUGH
THE FORECAST PERIOD...WITH EXTENDED PERIODS OF CHILLY WEATHER.

MODELS ARE IN GENERAL AGREEMENT WITH MAJOR FEATURES THROUGH MID
WEEK...THEN DIVERGE SLIGHTLY(AS NORMAL). THE PERIOD BEGINS WITH A
LONG WAVE TROUGH MIGRATING OVER THE AREA...THEN AFTER A BRIEF PERIOD
OF RIDGING...THE UPPER AIR PATTERN MIGRATES BACK TO A NORTHWEST FLOW
REGIME THROUGH THE MID AND LATER PARTS OF THE WORK WEEK. BY EASTER
WEEKEND A LONG WAVE RIDGE IS FORECAST TO BUILD OFF THE ROCKIES.
SO...OTHER THAN TUESDAY AND SATURDAY...THE GENERAL RULE IS COOLER
THAN NORMAL AND SHOWERY WEATHER.

SOME SPECIFICS...INCREASED CHANCES OF RAIN OR SNOW ON SUNDAY NIGHT
AS ALL MODELS ARE SLOWING THE PROGRESS OF THE SYSTEM AND THUS
CHANCES OF PRECIP LINGER OVER THE AREA. TEMPS WILL BE VERY NEAR THE
LIQUID/FROZEN CHANGEOVER SO WILL MENTION MIXED PRECIP...EXCEPT FOR
THE MOST NORTHERN AREAS OF THE PRECIP SHIELD WHERE IT WILL BE COLD
ENOUGH BOTH ALOFT AND AT LOW LEVELS TO SUPPORT SOME VERY LIGHT SNOW.

A SEASONABLY COLD AIRMASS THEN SETTLES INTO THE AREA ON MONDAY WITH
DRY WEATHER BUT TEMPERATURES SOME 15 DEGREES BELOW NORMAL.

A BRIEF MODERATION IN TEMPS AND A DRY PERIOD IS EXPECTED TUESDAY IN
ADVANCE OF THE NEXT SYSTEM. THE SOUTH WINDS IN ADVANCE OF THIS
SYSTEM COMBINED WITH FAIRLY CLOUD-FREE SKIES ALLOW FOR PLENTY OF
INSOLATION AND PROBABLY THE BEST DAY OF THE WORK WEEK FOR OUTDOOR
ACTIVITIES.

THE EFFECTS OF A NORTHWEST FLOW REGIME BEGIN IN EARNEST ON WEDNESDAY
AND CONTINUE THROUGH FRIDAY. A SURFACE COLD FRONT IS FORECAST TO
PASS ON WEDNESDAY KEEPING MAX TEMPS WELL BELOW NORMAL. A LACK OF
MOISTURE ALLOWS THE FRONT TO PASS WITHOUT PRECIPITATION. BY
WEDNESDAY NIGHT THE FORECAST AREA IS UNDER THE INFLUENCE OF STRONG
DYNAMICS...BUT LIMITED LOW LEVEL MOISTURE. PRECIP IS MENTIONED FROM
WEDNESDAY NIGHT THROUGH FRIDAY IN SCATTERED SHOWERS...BUT THE AMOUNT
OF RAINFALL IS EXPECTED TO BE ON THE LIGHT END (LIKELY LESS THAN
0.25 INCH AT ANY GIVEN SPOT THROUGH THE PERIOD). IT ALSO WILL NOT BE
RAINING ALL THE TIME...MORE LIKELY PASSING LIGHT SHOWERS ON AND OFF
THROUGH OUT THE PERIOD. BECAUSE OF THE EXTENSIVE CLOUD COVER AND
SOME REINFORCING SHOTS OF COOL AIR...TEMPERATURES WILL BE 10 TO 20
DEGREES COOLER THAN NORMAL THROUGH THE PERIOD. NORTHERN AND WESTERN
AREAS MAY SEE A FEW SNOWFLAKES MIXED WITH THE RAIN AT TIMES DUE TO
TEMPS HOVERING NEAR FREEZING AT TIMES (ESPECIALLY OVERNIGHT AND
EARLY MORNING HOURS). THE MIX IS NOT MENTIONED AT THIS TIME...BUT
WILL BE MONITORED AND AS WE GET CLOSER TO THE EVENT...BETTER
DETAILED TEMPERATURE PROFILE DATA WILL ALLOW FOR A BETTER
DETERMINATION OF PRECIP TYPE.

FINALLY...IT APPEARS SATURDAY WOULD BE A NICE DAY FOR OUTDOOR
ACTIVITIES...IF EVERYTHING PLAYS OUT AS CURRENTLY FORECAST. WE WILL
HAVE TO CONTINUE TO MONITOR THE PATTERNS THROUGH THE WEEK AND SEE
WHAT CHANGES ARE IN STORE.

&&

.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 107 PM CDT SAT APR 12 2014

THE MAIN HIGHLIGHTS OF THIS TAF PERIOD INCLUDE INCREASING CHANCES
FOR SHOWERS/THUNDERSTORMS ESPECIALLY DURING THE FINAL 6
HOURS...ALONG WITH A NOTABLE INCREASE IN NORTHERLY WIND SPEEDS
DURING THE FINAL 12 HOURS. ALTHOUGH CONFIDENCE REMAINS QUITE HIGH
IN VFR CEILING/VISIBILITY THROUGH AT LEAST THE FIRST 15 HOURS INTO
LATE TONIGHT...THE LATTER 9 HOURS OF THE PERIOD INTO SUNDAY
MORNING ARE FAIRLY LOW CONFIDENCE AND ARE PRONE TO PLENTY OF
ADJUSTMENTS. STARTING OFF THIS AFTERNOON INTO AT LEAST THE FIRST
PART OF TONIGHT...BREEZES WILL PREVAIL FROM A NORTH-NORTHEAST
DIRECTION WITH SUSTAINED SPEEDS GENERALLY UNDER 15KT AND ANY
CEILING WELL INTO VFR RANGE. THEN LATE TONIGHT INTO SUNDAY
MORNING...NORTH WINDS WILL STEADILY INCREASE...WITH GUST POTENTIAL
INCREASING TO AT LEAST 35KT THROUGH THE LAST SEVERAL HOURS OF THE
PERIOD. AS FOR PRECIPITATION/CEILINGS...ITS LOOKING INCREASINGLY
LIKELY THAT THERE IS VERY LITTLE RISK FOR SHOWERS/STORMS MUCH
BEFORE SUNRISE...WITH MUCH BETTER CHANCES COMING INTO PLAY FOR THE
LAST 3-6 HOURS OF THE PERIOD. GIVEN THAT THIS SHOWER/STORM CHANCE
IS STILL WELL INTO THE SECOND HALF OF THE TAF PERIOD...DID NOT
FEEL CONFIDENT ENOUGH TO ADVERTISE ANY TEMPO/PREVAILING GROUP FOR
PRECIPITATION YET...BUT INSTEAD HAVE A VICINITY THUNDERSTORM
(VCTS) IN PLACE STARTING AT 11Z.


&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM 9 AM TO 7 PM CDT SUNDAY FOR NEZ039>041-
     046>049-060>064-072>077-082>087.

KS...WIND ADVISORY FROM 9 AM TO 7 PM CDT SUNDAY FOR KSZ005>007-
     017>019.

&&

$$

SHORT TERM...PFANNKUCH
LONG TERM...EDDY
AVIATION...PFANNKUCH



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