Area Forecast Discussion
Issued by NWS Goodland, KS

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000
FXUS63 KGLD 200905
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
205 AM MST Mon Feb 20 2017

.UPDATE...
Issued at 922 PM MST Sun Feb 19 2017

Update to forecast sent to adjust cloud cover wording for the
entire CWA. Latest satellite trend continues to show ample
mid/high clouds still streaming northward thru the Tri State
region...with little push eastward. As a result will slow
clearing trend to well after midnight from west to east...with
better conditions by 12z Monday. For precip...based on latest
radar trend...precip to the ESE looks to remain out of the
area...as does the precip over north central Colorado. Current
forecast has this covered well. Temp trend looks very good and no
changes made at this time.

&&

.SHORT TERM...(This evening through Monday)
Issued at 126 PM MST Sun Feb 19 2017

Latest upper air analysis shows a trough over the Desert Southwest
extending into Mexico.  To the east a ridge was located over the
Mississippi River Valley. Ahead of the trough water vapor was
being channeled north over the Plains. Accompanying the trough
was much drier air.

This evening have low confidence for any rainfall development.  As
the upper level trough approaches the Tri-State Area lift
increases, but drier air also moves in. The only chance for
rainfall currently looks to be over the eastern part of the
forecast area where weak lift will be coupled with increasing
moisture ahead of the encroaching dry air. Any storms that develop
will shift east before midnight. Meanwhile over to the northwest
a band of elevated moisture does move across Yuma and neighboring
counties, but it is not very deep. Am not expecting any
precipitation from that as a result.

The breezy winds will continue well into the evening due to the
tight pressure gradient ahead of a pre-frontal trough that will
move through overnight. As the trough moves through south winds
will decline and turn to the northwest. The northwest winds will
gradually increase as the pressure gradient tightens behind the
trough. A weak cold front will accompany the increasing winds
overnight. Behind the front dew points will lower as drier air
moves in.

Lows will be cooler than last night in East Central Colorado due to
the cold front and drier air.  To the east lows will be the same to
a few degrees warmer.  The lows over the east continue to be similar
to what normal highs for this time of year would be.  The very warm
lows from last night and tonight may well set/tie records for the
warmest low for today.

Monday northwest winds will increase in the morning, with winds
reaching a peak around noon.  During the afternoon winds will
gradually decline as the low level jet overhead weakens.  Highs will
be cooler than today, despite the clear sky, due to the cooler air
mass.  The breezy winds and dry air may lead to critical fire
weather conditions.  See fire weather section for further
information.

.LONG TERM...(Thursday through Sunday)
Issued at 204 AM MST Mon Feb 20 2017

Thursday-Friday: GFS/ECMWF are in general agreement on H5 pattern,
showing negatively tilted open shortwave trough moving over our
CWA, with several strong lobes of vorticity across our north. H7
low becomes broadly closed off, and current GFS/ECMWF are weaker
than current GEM and old ECMWF of 24hr ago. Confidence is still
high in precipitation (particularly north), and what should be a
clean rain to snow transition. ECMWF is a little faster with cold
front and may have temps falling in the afternoon and an earlier
change over. Precip is shown to be light to moderate, and system
is fairly progressive so accumulation potential is somewhat
limited compared to the heavier amounts shown 24hr ago.

While current consensus and conservative timing of change over may
only support 0.5-1", adjusting latest QPF trends for an earlier
transition to snow could support upwards of 3" (advisory) in our
north. Warm ground temps will play a role in melting snow that
falls and potential for blowing snow off ground, so that does
limit confidence on potential impacts. At the same time winds
increase sharply behind front and if this coincides with any
falling snow, then blowing snow would occur. Visibility
restrictions would play more of a role if this coincides with
moderate pockets or bands of snow (can`t rule this out).

Saturday-Sunday: Models show west to southwest flow redeveloping,
however heights aloft do not completely recover and a series of
shortwave troughs moving across Northern Plains reinforce
lingering quasi-stationary front near our CWA. Lee trough
attempts to develop towards our southwest, but there isn`t a lot
of consistency on the surface pattern due to this more
active/progressive pattern aloft. Result should be that temps
linger near seasonal levels at least, and I could see periods
where current highs are actually too warm if low clouds persist
north of this front. There are occasional precip chances with
progressive shortwave troughs, particularly on Sunday with a
stronger shortwave trough passage. There is not a lot of
consistency on evolution of this feature at this time, or strong
consensus on precip most periods. I kept 20/30 PoPs in place where
current blend/mean places them due to lower confidence on details
at this range.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1037 PM MST Sun Feb 19 2017

Conditions...VFR with SCT-BKN200-250 trending to SKC by end of
forecast period.

Precip/Wx....None expected.

Winds........For KGLD...from 06z-0930z SSW 10-20kts. 0930z-22z
NNW 10-20kts w/ gusts to 30kts after 14z. From 22z Mon-02z Tues NW
around 10kts. 02z Tuesday onward...SW around 10kts.

For KMCK...from 06z-12z SSW 10-20kts. 12z-22z NNW 10-20kts w/
gusts to 30kts after 15z. 22z Mon-02z Tues NW around 10kts. 02z
Tuesday onward...SW around 5-10kts.

Low Level Wind Shear(LLWS)...for KGLD 06z-08z 220@45kts and 0930z-
14z 320@45kts. For KMCK...06z-10z 220@40kts and 12z-15z 330@45kts.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Fire Weather Watch from 11 AM MST /noon CST/ this morning
     through this afternoon for KSZ001-013-027-041-042.

CO...Fire Weather Watch from 11 AM MST this morning through this
     afternoon for COZ252>254.

NE...NONE.
&&

$$

UPDATE...JN
SHORT TERM...JTL
LONG TERM...DR
AVIATION...JN



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