Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 02/04/21

Area Forecast Discussion...Updated

National Weather Service Phoenix AZ

 Issued by National Weather Service Tucson AZ
428 PM MST Wed Feb 3 2021

.UPDATE...Updated aviation discussion.

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.SYNOPSIS...
A weak weather system approaching from the northwest will bring
breezy conditions by this evening before bringing a dry cold front
through the region early on Thursday. Despite the cooler conditions
Thursday and Friday, near normal temperatures are expected both
days. The dry conditions are likely to persist through the weekend
into early next week as weak high pressure dominates the region,
while allowing for temperatures to warm to slightly above normal
through early next week.

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.DISCUSSION...
The low temperature this morning in Phoenix shattered the daily
record warm low by 8 degrees, with 64F, but temperatures are warming
slightly slower than they did yesterday with mid level clouds
hanging around over south central AZ. These clouds continue to clear
this afternoon with only higher cirrus remaining. H5 heights have
also decreased from this time yesterday ahead of a trough pushing
southeast through the Great Basin and slight cooling in the low
levels was noted in ACARS aircraft soundings. So, this afternoon`s
high will likely come a degree or two shy of yesterdays in most
places, but will still be unseasonably warm. Phoenix has already
reached 80F.

With the aforementioned trough moving through the Great Basin,
breezy westerly winds should develop across the CWA by late this
afternoon and evening as the trough continues its progression
southeastward through Utah and into western Colorado tonight. Still
anticipating a dry cold front to then move through Arizona early
Thursday morning. Drier air will work in behind the front resulting
in generally clear skies for much of Thursday, while the cooler air
mass will keep highs mostly near normal. Winds will also shift more
northerly to northwesterly post front, with stronger winds becoming
focused along the Lower Colorado River Valley. Gusts along the river
valley Thursday may reach up to 30 to 35 mph.

For Friday into the weekend, a deep trough will become dominant
across the central part of the country, with the trough somewhat
influencing our region keeping a dry northwesterly flow regime in
place.Temperatures will warm slightly into the weekend with highs
likely topping out closer to 75 degrees across the western deserts
and in the lower 70s elsewhere. There is still a good deal of
uncertainty with how the deep trough over the eastern 2/3s of the
country will influence our heights and temperatures late in the
period, but median temperature guidance overall depicts little
change in temperatures through early next week. Given the
uncertainty in the positioning of the trough, guidance temperature
range remains quite large for Sunday and beyond. Either way, the
pattern looks to remain dry for the foreseeable future, with overall
little chance of any meaningful weather systems affecting the Desert
Southwest likely through the middle of next week.

&&

.AVIATION...Updated at 2310Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT No major
weather concerns will exist through Thursday evening as high clouds
generally thin. Confidence is good that west winds will prevail well
into the overnight, and a brief gust 15-20kt may be possible this
evening. Greater uncertainty exists whether winds will make the
switch to easterly Thursday morning or become variable in direction.
Regardless, directions should quickly go back to a westerly
component late Thursday morning.

Southeast California/Southwest Arizona including KIPL and KBLH:

Occasionally gusty winds will be the only weather issue through
Thursday evening under passing high clouds. After a period of S/SW
winds this evening, northerly winds will be favored at KBLH with
gusts in excess of 20kt common Thursday afternoon. Westerly winds
will be preferred at KIPL, and even a briefly stronger gusts would
be possible.

&&

.FIRE WEATHER...
Friday through Tuesday:
Dry conditions under weak high pressure are expected through much
if not all of the period. Temperatures through the period will be
around or slightly above normal. Winds through the period should
overall be on the light side as high pressure becomes dominant.
Low moisture levels should result in minimum RHs mostly falling to
between 12-20% on most days.

&&

.SPOTTER INFORMATION STATEMENT...
   Spotters should follow standard reporting procedures.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

DISCUSSION...Benedict/Kuhlman

$$