Area Forecast Discussion
Issued by NWS Goodland, KS

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FXUS63 KGLD 201735

Area Forecast Discussion
National Weather Service Goodland KS
1135 AM MDT Wed Sep 20 2017

Issued at 1135 AM MDT Wed Sep 20 2017

Update to forecast sent for issuance of Red Flag warning. Please
refer to the Fire Wx section below.


.SHORT TERM...(Today through Friday night)
Issued at 313 AM MDT Wed Sep 20 2017

Large scale upper low remains in place over the northern Rockies,
with a shortwave trough now moving east of our CWA. WV imagery
indicates subsidence in place over our CWA, with drying in the mid-
upper levels. At the surface a cold front has pushed through our
CWA, and surface high pressure has built into our CWA.

Dry conditions should persist through Friday morning as a deep
dry/subsident air mass remains in place. Post frontal air mass today
should support seasonal high temperatures in the upper 70s/near 80F
for most of our CWA. The trough over the Pacific NW will deepen into
the southwest US and southwest flow will redevelop late tonight into
Thursday. Lee trough/dry line develops Thursday, along with
unseasonably hot temperatures in the upper 80s to upper 90s.
Increasing southerly gradient will result in windy conditions with
daytime gusts Thursday around 35 mph (possibly higher).

Friday-Friday night: Jet stream begins to slide east, and southwest
flow in the mid to upper levels begins to pull Pacific/Gulf moisture
into the Central High Plains. Showers/thunderstorm chances will be
increasing Friday afternoon and Friday night, with initiation Friday
afternoon along trough axis along/east of Colorado border. Coverage
will be a question during these periods due to drier lower levels,
however severe parameters are beginning to line up and MLCAPE 2000
J/KG (or higher) and deep/strong unidirectional shear could
support an organized severe threat Friday afternoon through
Friday evening.

.LONG TERM...(Saturday through Tuesday)
Issued at 240 AM MDT Wed Sep 20 2017

A highly amplified synoptic pattern remains in place for the
extended period with a deep trough across the western states and a
ridge in the east. A nearly stationary cold front and associated
theta-e boundary, will be situated from southwest to northeast
across the CWA on Saturday. There will be a good chance of showers
and embedded thunderstorms through much of the day with a chance of
strong to severe thunderstorms during the afternoon and evening
hours along an axis of higher instability and shear. PW values
remain high, generally in the 1.25 to 1.60 inch range (GFS) on
Saturday, thus we will likely see periods of moderate to heavy
rainfall, especially within the stronger storms.

The theta-e boundary slides slightly eastward as we head into
Sunday. PW remains high, in the 1.35 to 1.70 inch range with lower
environmental instability across the region as compared to previous
days. Although severe storms are not expected, a few stronger storms
could still develop in our eastern most counties. Moderate to heavy
rainfall is expected throughout the day, especially in the eastern
two thirds of the CWA. Storm total rainfall estimates are in the 3
to 4 inch range but this will likely fluctuate as new data is made

We will begin to see reduced rain chances from west to east on
Monday as the surface boundary slides eastward. Much cooler
conditions are expected as daytime highs will only climb into the
60s. Tuesday will bring dry weather with highs in the 70s.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1114 AM MDT Wed Sep 20 2017

VFR conditions expected for both sites with a SKC-FEW250 mix.
Winds will be variable for both sites thru about 00z-01z
Thursday...then SE around 10kts. By 14z-15z...winds shift to the S
around 10kts. LLWS for both sites starting around 00z-01z thru
14z-15z...180-200 degrees @ 40-45kts.


Issued at 1135 AM MDT Wed Sep 20 2017

Low dewpoint temps will develop behind a surface trough/dry line
on Thursday, and combine with unseasonably hot temperatures to
produce low RH values of 15% or lower. Confidence is high that
winds will be 25 mph or higher during the day across our CWA. The
combination of the aforementioned has prompted the issuance of the
Red Flag Warning for the entire Tri State region for Thursday
afternoon into early evening.


KS...Red Flag Warning from noon MDT /1 PM CDT/ to 7 PM MDT /8 PM CDT/
     Thursday for KSZ001>004-013>016-027>029-041-042.

CO...Red Flag Warning from noon to 7 PM MDT Thursday for COZ252>254.

NE...Red Flag Warning from noon MDT /1 PM CDT/ to 7 PM MDT /8 PM CDT/
     Thursday for NEZ079>081.



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