Area Forecast Discussion
Issued by NWS Goodland, KS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KGLD 211630
AFDGLD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
930 AM MST WED JAN 21 2015

.UPDATE...
ISSUED AT 911 AM MST WED JAN 21 2015

OVERALL FORECAST IN GENERAL LOOKS VERY REASONABLE.  LATEST RADAR
AND MODEL DATA INDICATE THE BAND OF SNOWFALL IS FORMING ALONG A
BAND OF 700-600MB FRONTOGENESIS...WITH SOME 600-500MB LAYER LIFT
ALSO PLAYING A ROLE. THETA-E LAPSE RATES IN THE 700-600MB LAYER
ARE 5-8K/KM...FAIRLY STABLE...WHILE LAPSE RATES IN THE 600-500MB
LAYER ARE CLOSER TO 0K/KM. WILL BE INTERESTING TO SEE IF THE SNOW
TAPS INTO THE LESS STABLE ENVIRONMENT THIS MORNING.

AS THE MORNING PROGRESSES THE LIFT WILL MOVE NORTHWARD THEN
DECLINE DURING THE AFTERNOON. AT THIS POINT AM THINKING THE
HIGHEST SNOWFALL AMOUNTS WILL BE 3 INCHES OVER FAR SOUTHERN
CHEYENNE AND GREELEY COUNTIES...WITH 1-2 INCHES IN GENERAL. THE
HIGHER SNOWFALL AMOUNTS WILL BE TO THE SOUTH AND WEST OF THE TRI-
STATE AREA...WHERE THE MIDLEVEL LIFT WILL BE STRONGEST. AM
THINKING THE MAJORITY OF THE SNOWFALL WILL OCCUR DURING THE
MORNING...TAPERING OFF DURING THE AFTERNOON.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 258 AM MST WED JAN 21 2015

AS OF 3 AM CST...2 AM MST...SKIES ACROSS THE TRI-STATE REGION ARE
OVERCAST SOUTH OF A LINE FROM WRAY COLORADO TO HILL CITY KANSAS.
TEMPERATURES ARE IN THE UPPER 20S TO LOW 30S. WINDS ARE NORTHWEST AT
5 TO 10 MPH. LATEST RADAR TRENDS INDICATE A BAND OF LIGHT SNOW ALONG
THE FRONT RANGE BETWEEN DENVER AND PUEBLO...EXTENDING EAST TO NEAR
LIMON AND LAMAR COLORADO. TWO STRONG SHORTWAVE TROUGHS WERE LOCATED
OVER THE WESTERN UNITED STATES. THE FIRST IS LOCATED ALONG THE IDAHO
AND WYOMING BORDER. ANOTHER IS LOCATED ALONG THE CALIFORNIA AND
ARIZONA BORDER. THE FIRST SHORTWAVE TROUGH IS THE MAIN PLAYER IN
TODAY`S WINTER WEATHER.

MAIN SHORT-TERM FORECAST CONCERN IS SNOW ANTICIPATED TODAY INTO THIS
EVENING. FOCUSED THIS DISCUSSION ON TODAY/TONIGHT AS THE WEATHER
AFTER TONIGHT IS QUITE DULL WITH NO HAZARDOUS CONDITIONS FORECAST.

SNOW DEVELOPMENT/INTENSIFICATION IS ADVERTISED TODAY BY MANY PIECES
OF GUIDANCE. THIS HAPPENS AS THE NORTHERN SHORTWAVE TROUGH SURGES
SOUTH. IN ADDITION TO LIFT PROVIDED BY THE SHORTWAVE...WIDESPREAD
FRONTOGENESIS DEVELOPS AROUND 700 MB...PARTICULARLY ACROSS SOUTHEAST
COLORADO AND SOUTHWEST KANSAS. BASED ON FORECAST SOUNDINGS AND HIGH-
RESOLUTION FORECAST GUIDANCE...SNOW SHOULD BEGIN AROUND SUNRISE IN
EAST COLORADO. SNOW GRADUALLY EXPANDS IN COVERAGE AND INTENSITY BY
LATE MORNING AND REACHES THE PEAK AROUND TO SHORTLY AFTER NOON.
WORST CONDITIONS IN TERMS OF HEAVIEST SNOW/LOWEST VISIBILITY ARE
FORECAST BETWEEN 10 AM AND 2 PM MST. LIFT FROM THE PASSING SHORTWAVE
AND WEAKENING FRONTOGENESIS WILL LEAD TO A WANING SNOW BAND BY LATE
AFTERNOON AND CLEARING OUT COMPLETELY BY LATE EVENING.

THIS FORECAST DOES COME WITH A FEW CONCERNS. FIRST...THERE WILL BE A
SHARP GRADIENT FOR SNOW ACCUMULATIONS. THE DIFFERENCE BETWEEN A
TRACE OF SNOW AND UP TO 4 INCHES IS AROUND 50 MILES. ANY SLIGHT
SHIFT IN THE MOVEMENT OF THIS SYSTEM COULD DRASTICALLY EFFECT SNOW
TOTALS. SECOND...TEMPERATURES WILL HOVER AROUND TO JUST BELOW
FREEZING FOR THIS ENTIRE EVENT. THEREFORE...SNOW RATIOS SHOULD BE ON
THE LOW SIDE COMPARED TO NORMAL. WENT WITH A 12:1 SNOW:LIQUID RATIO
BUT WE COULD OBSERVE A RATIO CLOSER TO 10:1 AS WAS NOTED LAST NIGHT.
THIS WOULD ALSO HAVE AN IMPACT ON SNOW TOTALS IF THE PRECIPITATION
FORECAST IS SLIGHTLY OFF.

OVERALL...FELT MOST CONFIDENT IN REACHING ADVISORY LEVEL SNOW
TOTALS...OR GREATER THAN 3 INCHES...ACROSS CHEYENNE COUNTY COLORADO
AND GREELEY COUNTY KANSAS. THE WESTERN THIRD OF KIT CARSON COUNTY
COLORADO MAY APPROACH 3 INCHES AS WELL BUT FELT THE SHORTWAVE AND
FRONTOGENESIS WOULD BE TOO FAR SOUTH AND MOVE TOO QUICKLY TO ALLOW A
LONG ENOUGH PERIOD OF ACCUMULATING SNOW. ALL SNOW SHOULD REMAIN
SOUTH OF AN AKRON COLORADO TO GOODLAND TO SCOTT CITY KANSAS LINE.
OUTSIDE OF THE COUNTIES INCLUDED IN THE ADVISORY...ONLY LIGHT
ACCUMULATIONS ARE FORECAST...GENERALLY A TRACE TO ONE INCH.

.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 258 AM MST WED JAN 21 2015

ONLY PROBLEM THROUGH THIS PERIOD WILL BE THE MINOR CONCERN OF HIGH
TEMPERATURES. THIS CONCERN HAS CHANGED DRAMATICALLY FROM YESTERDAY
WHEN SNOW CHANCES SATURDAY NIGHT AND HIGH WINDS ON SUNDAY WERE THE
BIG ISSUES. MODELS CHANGED A LOT FROM 24 HOURS AGO. 00Z MODEL DATA
CONTINUED THE TRENDS SHOWN BY THE 12Z DATA. MODELS CONTINUE TO
SHOW A VERY DRY AIR MASS WITH NO SUSTAINED SIGNIFICANT LIFT TO
HELP SATURATE THE AIR MASS. THE MAIN LIFT REMAINS NORTH AND EAST
OF OUR AREA. SO NOT ONLY WILL CONTINUE THE DRY FORECAST FOR
SATURDAY NIGHT BUT ALSO FOR THE REMAINDER OF THE PERIOD DUE TO A
LACK OF MOISTURE AND SIGNIFICANT LIFT.

MODELS CONTINUE TO BUILD MID/UPPER LEVEL RIDGE INTO THE WESTERN
PORTION OF THE COUNTRY. THE MODELS LOOK TO BE DOING THIS A LITTLE
FASTER AND FURTHER EAST THAN YESTERDAY. AS A RESULT...THE SYSTEM
THAT WAS DIGGING INTO THE NORTH CENTRAL PORTION OF THE COUNTRY IS
FURTHER NORTHEAST AND ALSO NOT AS STRONG. CONSEQUENTLY...THE
HIGHER WINDS ARE NOW PULLED FURTHER NORTHEAST. EVEN THOUGH IT
LOOKS LIKELY THAT WINDS WILL NOT REACH WARNING CRITERIA...IT WILL
STILL BE A WINDY DAY.

TEMPERATURES LOOK TO BE ABOVE NORMAL THROUGH THE PERIOD. WITH THE
RIDGE BUILDING INTO THE AREA AND DOWNSLOPE WINDS OCCURRING OVER
MOST OF THIS PERIOD...THIS DOES LOOK REASONABLE. SOME TIMING
DIFFERENCES IN THE MODELS BRINGING THROUGH COLD FRONTS AND THE
POSSIBILITY OF THICKER HIGHER LEVEL CLOUDS LEADS TO A SMALL DEGREE
OF UNCERTAINTY AS TO HOW WARM THE MAXES WILL GET. SO I LEFT ALONE
THE TEMPERATURES GIVEN TO ME BY THE INIT. HOWEVER...THERE IS SOME
POTENTIAL FOR THESE TEMPERATURES TO BE TOO COOL GIVEN THE RIDGING
AND DOWNSLOPE WINDS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 440 AM MST WED JAN 21 2015

UPPER LEVEL IS SPREADING SOME SNOW TOWARD KGLD FROM THE WEST AND
SOUTHWEST. MODEL GUIDANCE IS CONSISTENT HAVING THE NORTHERN EDGE
OF THIS LIGHT SNOW VERY KGLD FROM MID MORNING UNTIL MID AFTERNOON.
AT THIS TIME THINKING IS TO HAVE THE MAIN SNOW REMAIN TO THE WEST
AND SOUTH OF KGLD. SO KEPT VCSH FOR THE SNOW AND VFR/JUST ABOVE
MVFR AT KGLD FROM 16Z UNTIL 22Z. AFTER THAT THE CEILINGS WILL RISE
WITH WHATEVER SNOW THERE WAS MOVING WELL SOUTH OF THE SITE.

FOR KMCK...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. FOR
BOTH SITES...WIND SPEEDS ARE EXPECTED TO STAY AT 12 KNOTS OR LESS.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING FOR KSZ041.

CO...WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING FOR COZ092.

NE...NONE.
&&

$$

UPDATE...JTL
SHORT TERM...RRH
LONG TERM...BULLER
AVIATION...BULLER



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.