Area Forecast Discussion
Issued by NWS Cheyenne, WY

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

FXUS65 KCYS 270438

Area Forecast Discussion
National Weather Service Cheyenne WY
1038 PM MDT Wed Oct 26 2016

Issued at 842 PM MDT Wed Oct 26 2016

In a recent update went ahead and issued a Fire Weather Watch for
Thursday. Looking at the past week, we have been a little high on
forecast dewpoints during the afternoon. So lowered tomorrows
dewpoints a couple degrees which puts areas east of the Laramie
Range as critical. Looking at GFS forecast soundings, we should
easily mix down 30-35kts of wind here at Cheyenne and up by
Douglas. Thus the Watch issuance. WIll let the mid crew pull the
trigger on a red Flag Warning once they see the 00Z run.


.SHORT TERM...(This evening through Friday night)
Issued at 220 PM MDT Wed Oct 26 2016

The unseasonably warm weather will hang on over the CWA through
Friday under an upper ridge that will build over the region
Thursday then weaken some as it shifts east on Friday. varying
amounts of high clouds will pass across but skies will be mostly
clear through Friday morning. A lee trough will deepen over the
high plains Thursday resulting in some breezy conditions around
the mountains Thursday afternoon through Friday but not too
strong. A shortwave will approach the area Friday night wil a weak
front drops south over the plains. The shortwave should bring some
scattered showers to mainly northern and western parts of the CWA
beginning Friday night. A bit of snow possible over the highest
peaks late Friday night with cold air generally lacking.

.LONG TERM...(Saturday - Wednesday)
Issued at 220 PM MDT Wed Oct 26 2016

The main story in the extended forecast period will be the passage
of a strong mid-level shortwave and associated cold front sometime
from late Sunday through Monday. The GFS/NAM are both in agreement
with this feature, so confidence is high in a widespread high wind
episode over the CWA. The GFS H85 CAG-CPR gradients approach 70-80
meters by 12z Monday with a broad swath of 60 knot H7-H8 flow over
a large part of the CWA along with steep lapse rates. The ECM soln
is farther south with the system and would make warning level wind
a bit less likely, but still a very windy pattern. Strongest winds
per the GFS would occur over the wind corridors around 06z Mon and
spread out onto the plains as a strong bora by 12z with impressive
subsidence suggested by GFS omega fields. Precipitation chances w/
the fropa are not expected to be high, but a few rain/show showers
will be possible over western and northern zones.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1036 PM MDT Wed Oct 26 2016

VFR conditions with mainly clear skies and gusty winds during the
day light hours. High pressure overhead and to our south will keep
VFR conditions going for the forseeable future.


Issued at 220 PM MDT Wed Oct 26 2016

Warm and dry weather will hold over the area through Friday. A cool
front will drop south across the plains Friday night bringing a
little cooler temperatures for Saturday. Some showers are expected
Friday night into Saturday. Windy conditions are then expected
Saturday night into Sunday around the mountains.


WY...Fire Weather Watch from Thursday morning through Thursday
     afternoon for WYZ301-309-310.



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