Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/12/21
Area Forecast Discussion
National Weather Service Great Falls MT
743 PM MDT Fri Jun 11 2021
A warming and drying trend begins, today. By Tuesday, highs are
expected to reach into the triple digits across some areas. These
forecast temperatures are well above normal for this time of
year. Mid next week, temperatures are expected to cool a bit,
while still remaining above seasonal averages.
Increasing cloudiness is expected overnight across the region, along
with some overnight precipitation along The Divide. Otherwise, north
central, central and southwest Montana remain dry. Forecast is on
target; therefore, no updates will be made, at this time.
Today through Tuesday...
Weak upper level ridging dominates The Treasure State, today.
Expect dry conditions, even as a warming trend begins. With an
upper level closed area of lower heights located over North
Dakota, and the approach of a North Pacific Trof from the west, an
already weak ridge weakens further, and a tightening height
gradient across The Rocky Mountain Front favors widespread mildly
gusty winds across Montana. Perturbations in the flow aloft favor
some precipitation along The Great Divide overnight tonight and
into tomorrow morning. During this period, a strong closed upper
level area of higher heights strengthens over western
Texas/southern New Mexico causing a strong ridge to develop and
extend northward into The Canadian Northwest Territories. The
closed upper level height migrates northward, settling over The
Four Corners region. Expect dry conditions and warming
temperatures to continue, with highs reaching into the triple
digits across some areas, by Tuesday afternoon. Periods of gusty
winds are expected each day. As we progress through this period,
Relative Humidity (RH) values fall, and by Tuesday, RH values are
forecast in the the low to mid teens across most of our area.
Confidence is high in terms of the coming hot temperatures and low
RH values. Confidence is moderate in terms of meeting fire
weather wind criteria. With this anticipated hot, dry and windy
weather, we are closely monitoring fire weather concerns, and will
continue to update as necessary.
Wednesday through next Friday...
Wednesday, the afore mentioned upstream upper level North Pacific
Trof moves eastward and squeezes up against the Montana overhead
ridge, removing some mass from the ridge, and filling the trof a
bit. With a closed upper level area of lower heights located over
the Canadian Alberta/Saskatchewan region, and the closed high
heights over The U.S. Four Corners region, a strong cross barrier
flow sets up across The Rocky Mountain Front favoring strong gusty
winds across The North/South Rocky Mountain Front during the day
on Wednesday. Temperatures cool by about 10 to 15 degrees for the
remainder of this period keeping temperatures above normal, in the
mid 70s to 80s. Wednesday`s minimum RH values are forecast to
reside in the mid teens to low 20s, and with the expected gusty
winds, we continue to focus on fire weather concerns. Beginning
Thursday, numerical forecast model solutions become rather
divergent in their solutions for the last couple days of this
forecast period. Model agreement; and therefore, higher
confidence is found in the persistence of the upper level closed
heights over The Four Corners region; however, the behavior of
the atmosphere across The Northwest U.S. is somewhat uncertain.
Forecast confidence for Thursday and Friday is low to moderate, in
continued warm and dry weather with possible periods of gusty
winds. We continue to monitor and share forecast updates and
confidence as we move forward.
557 PM MDT Friday Jun 11 2021 (12/00Z TAF period)
VFR conditions are forecast at all airfields for the duration of
this TAF period. Winds are forecast to gust to 26KT. Funneled winds
impact light aircraft flying through mountain passes. Overnight,
precipitation is forecast along The Divide.
Refer to weather.gov/zlc for more detailed regional aviation weather
and hazard information.
.PRELIMINARY POINT TEMPS/POPS...
GTF 45 76 47 88 / 10 10 0 0
CTB 43 69 43 84 / 10 10 0 0
HLN 48 79 51 91 / 0 0 0 0
BZN 43 81 46 90 / 0 0 0 0
WYS 33 73 36 85 / 0 0 0 0
DLN 43 78 46 88 / 0 10 0 0
HVR 46 77 49 88 / 0 0 0 0
LWT 43 76 47 85 / 0 0 0 0