Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/19/22
Area Forecast Discussion
National Weather Service La Crosse WI
1053 PM CDT Tue Oct 18 2022
.DISCUSSION...(This evening through Tuesday)
Issued at 235 PM CDT Tue Oct 18 2022
Key Messages:
- Low afternoon relative humidity levels Wednesday
- Pattern shift expected for late week allow for rain/thunder
chances and warmer temperatures
Tonight and Wednesday...
Continual northwest flow from the upstream upper level low is
keeping the cold air in place through tonight with minimum
temperatures dipping into the 20s for most of the area. Winds will
abate this evening with a weakening surface pressure gradient,
resulting in not as cool wind chills into Wednesday morning.
Primary forecast concern is dry airmass in place with dewpoint
temperatures in the teens west of the Mississippi River to low 20s
east of the Mississippi River. Dewpoint temperatures off the
surface for Wednesday plummet according to high resolution
forecast soundings. Also evident in situ observations northwest of
the forecast area this afternoon. A stout 850mb-centered
temperature inversion, subsiding air, and weak low level lapse
rates will inhibit deep mixing into this drier air mass. However,
if maximum daytime surface temperatures can overachieve above
forecasted, may be able to slightly tap in and dry out further.
Currently forecasted relative humidities reach the low 20 percents
for select parts of northeast Iowa and southeast Minnesota. Not
an easy feat for surface temperatures to overachieve given low
October sun angle. Have decreased dewpoint temperatures a couple
of degrees lower than National Blend guidance at this time.
Thursday through Monday...
A pattern shift is finally expected to take place allowing the
region to break out of the recent cold snap. By the middle of the
week, the upper level low and long wave trough that has been
parked over the eastern half of the country will finally weaken
and move off toward the East Coast. This will initially allow some
weak ridging aloft to build in before the flow transitions to a
zonal flow for the end of the week and then becoming southwest
flow pattern over the weekend. The models are fairly good
consensus on this pattern change with only some slight differences
by the weekend on the speed with which the developing long wave
trough will advance east.
The first chance for some precipitation looks to be Sunday
afternoon and evening as a short wave trough out ahead of the long
wave trough gets caught in the southwest flow and pushed across
the region. The rain chance then look to continue as similar
scenario should play out Sunday night before the main system looks
to advance into the region Monday. A rumble or two of thunder
could occur ahead of the main system as with the 18.00Z ECMWF
suggesting around 250 J/kg of MU CAPE could be in place Sunday
afternoon and night across mainly the western parts of the local
area. Probably not enough instability to be concerned about severe
weather but the CSU machine probabilities do have a small signal
over the area for Sunday with an axis of higher probabilities
sitting over the Missouri River Valley into northern Minnesota.
Temperatures should respond nicely to the pattern change with
highs warming from the 40s Wednesday into the 60s for Friday
through Monday. A few spots could even top the 70 degree mark
Sunday afternoon. Overnight lows will warm into the 40s and 50s
during this period as well.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1053 PM CDT Tue Oct 18 2022
Should be a quiet aviation period with VFR conditions. Cyclonic flow
to the east continues to wrap some MVFR ceilings across parts of
northern and eastern Wisconsin with some question if they will
advect far enough west to impact KLSE. RAP trends this evening
suggest this is looking less and less likely so will keep out of TAF
for time being.
Otherwise surface ridge moves across tomorrow with lighter winds and
continued dry air.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...04/JAR
AVIATION...Shea
Area Forecast Discussion
National Weather Service Duluth MN
930 PM CDT Tue Oct 18 2022
.DISCUSSION...(This evening through Monday)
Issued at 329 PM CDT Tue Oct 18 2022
Summary: Quiet weather to finish out the week with a gradual warm
up. Next chance of precipitation will be in the Sunday/Monday
time frame.
The upper level low pressure that has affected the area has
finally moved far enough eastward to end all lake effect snow. The
main concern moving forward is the winds on the back side of the
low pressure system that sits over southern Ontario. The pressure
gradient will begin to subside this evening therefore, the northerly
winds will diminish this evening mainly over land. Elsewhere, the
winds along the lake will continue to be gusty through at least
tomorrow morning mainly along the South Shore.
Temperatures are expected to increase through the week,
especially later this week as two warm fronts move through the
region. The warm temperatures will certainly be felt on Sunday as
the second warm front moves through. This will also set up the
region for possible severe weather Sunday into Monday. Some long-
range models are indicating that isolated severe weather is
possible, but it is too early to tell given this is several days
out.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 645 PM CDT Tue Oct 18 2022
VFR conditions and mostly clear skies covered most of the
Northland early this evening. However, there were some lake
induced clouds over north central Wisconsin and some MVFR or low
VFR ceilings working south into the Arrowhead. We`ve made some
adjustments based on the RAP and satellite trends to bring in
more clouds to the Arrowhead and a bit further west and we also
expect more lake clouds in northern Wisconsin overnight. We do
expect MVFR ceilings to develop but a question remains both how
far west and south these will get. For now, we left ceilings out
of KDLH/KHIB but added to KHYR. KINL/KBRD should be too far west
to experience ceilings.
Gusty northerly winds will remain possible through the night along
portions of the North Shore, especially between Grand Portage and
Grand Marais where localized gusts around 35 knots will be
possible.
We expect any MVFR ceilings will rise to VFR or become scattered
through the day Wednesday.
&&
.MARINE...
Issued at 924 PM CDT Tue Oct 18 2022
Latest observations continue to show strong winds continued along
portions of the North Shore. Gusts of 30 to near 40 knots will be
possible tonight into Wednesday morning, especially close to
shore, due local affects. KGNA has been gusting to 30 to 37 knots
through the evening. There remains a chance an upgrade to a Gale
Warning may be needed, mainly from Grand Portage to Taconite
Harbor. It appears the stronger gusts are more localized and
closer to shore which prevents us from issuing one at this time.
Gusty winds will also continue along portions of the South Shore
and the Small Craft Advisory there remains in effect.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 24 44 29 49 / 0 0 0 0
INL 20 45 26 47 / 0 0 0 0
BRD 22 48 30 53 / 0 0 0 0
HYR 20 44 25 50 / 0 0 0 0
ASX 26 46 29 50 / 0 10 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 11 AM CDT Wednesday for LSZ140>142.
Small Craft Advisory until 10 AM CDT Wednesday for LSZ146>148-
150.
&&
$$
DISCUSSION...KSE
AVIATION...Melde
MARINE...Melde
Area Forecast Discussion
National Weather Service Fort Worth TX
604 PM CDT Tue Oct 18 2022
...New Short Term, Aviation...
.SHORT TERM... /NEW/
Update:
The current forecast is in good shape. Still expecting temperatures
to drop quickly after sunset once the boundary layer decouples
and wind speeds decrease. Will keep the Freeze Warning in place
across the northeast and leave the northwest zones just above
freezing due to the expected cloud cover.
79
Previous Discussion:
/Rest of Today through Tomorrow/
Dry northwesterly flow aloft will persist as a closed low that
has been residing over the desert southwest transitions into the
cyclonic flow around a deep eastern CONUS upper-level trough.
Northerly surface winds associated with surface high pressure over
the Plains will allow for continued cold-air advection and the
transport of drier air into North and Central Texas. Afternoon
highs today will likely peak in the upper 50s near the Red River
Valley to the mid 60s across Central Texas.
The coldest temperatures of the fall season thus far are on tap
for tonight into Wednesday morning. A Freeze Warning is in effect
from 3AM to 9AM Wednesday morning for locations along the Red
River Valley and across eastern North Texas. With mostly clear
skies and light surface winds in the forecast, radiational
cooling processes will be efficient. Expect overnight lows to fall
into the 30s across most locations to near 40 degrees around the
DFW Metroplex, with a few readings in the upper 20s not out of
the realm of possibility. We are currently forecasting an
overnight low of 39 degrees at DFW, which would come very close to
tying the record low temperature for October 19th of 38 degrees
set back in 1989. A plume of moisture within the 850-700mb layer and
subsequent cloud cover hinted by the latest RAP and HREF guidance
over the western portions of the CWA later tonight may help to
keep temperatures slightly warmer out west. A dry airmass noted by
low PWATs and dewpoints in the teens and low 20s will help to
limit the widespread frost potential. However, soil moisture from
recent rainfall may help to support some patchy areas of frost.
Surface winds look to take a more southerly shift by Wednesday
afternoon beginning a gradual warm-up into the latter half of this
week. Afternoon highs Wednesday will range from the low 60s across
East Texas to the low 70s west of the I-35 corridor.
Langfeld
&&
.LONG TERM... /Issued 349 PM CDT Tue Oct 18 2022/
Update:
/Moving Into The Weekend Into Early Next Week/
Only changes made were to lower lows and highs on Thursday, as low
dew point temperatures and winds 10 mph or less under clear skies
will still help temperatures to fall into the 40s for many areas
Thursday morning (NBM was mostly 50s). Meanwhile, for during the
day Thursday, the more substantial low level warm and moisture
advection will be delayed more toward later Friday and beyond.
As a result of the cooler start and advection delay, I dropped
highs down for most of the area, but especially the northeast half
of the area will the chilliest lows in the upper 30s and 40s will
occur. I just didn`t see a 40 degree+ diurnal range per the
aforementioned reasons.
On Friday/Saturday, just the opposite, though very gusty south-
southwest winds could temper heating a tad. But with plentiful
sunshine, these two days could be our toastiest with highs
averaging between 85 and 90 degrees (sorry, folks). With moisture,
wind, and clouds increasing this weekend into Monday, I also
raised lows a few degrees above NBM guidance with a blend of the
ECMWF Ensemble Guidance (ADJECE) and CONSALL numbers.
Otherwise, regarding our next system, cold front, and convective
rain chances early next week, deterministic GFS (wet and cooler)
and ECMWF (drier and slightly warmer) showed some significant
differences in the mid level pattern similar to what the previous
discussion below mentions. So I went with my mindset when this
occurs...that being, when in doubt, go to the ensembles. Both GEFS
and EPS ensemble guidance showed a strong lean toward the wetter
and cooler GFS deterministic solutions of a W/NW to E/SE trend of
increase convective chances with the impending cold front from
late Sunday night through early Tuesday morning. After that, all
bets are off as even ensemble members lose agreement later on
Tuesday and beyond. Either way, this minor late October heatwave
from Friday through Sunday should be short lived, as after the
good rainfall chances on Monday, we`ll see more Fall-like
temperature on Tuesday through the remainder of next week.
05/Marty
Previous Discussion:
/Wednesday Night through Early Next Week/
The long term portion of the forecast features a warming trend
and dry conditions through the weekend and the potential for some
showers/storms early next week.
As the surface high pressure moves to our east Thursday-Friday,
the southerly flow will return to the region. Temperatures will
quickly warm up into the 70s and 80s by Thursday and mid/upper 80s
by Friday. In addition to the warm temperatures, breezy conditions
are expected Friday and into the weekend in response to an approaching
trough. Fire weather concerns may increase across portions of the
western zones on Friday if the humidity values drop to near or
below 25%. Increasing humidity over the weekend should keep the
fire weather threat low. However, it will be warm and breezy with
afternoon highs in the mid/upper 80s to near 90 degrees in some
locations.
It appears the next upper trough will begin to move into the Great
Plains by early next week. Details on its track and progression
remains uncertain at this time due to a large spread between
model guidance. However, looking at the latest cluster analysis
they show a little over 50/50 chance of receiving some rainfall
over our area Monday-Tuesday. Forecast details will continue to be
adjusted over the next several days, but for now we will keep the
model blend for PoPs with at least a slight chance of
showers/storms Monday-Tuesday.
Sanchez
&&
.AVIATION... /NEW/
/00Z TAFs/
Great flying weather will continue around the region through
Wednesday afternoon with a mostly clear sky and no visibility
restrictions.
A breezy north wind early this evening will decrease quickly after
sunset. The wind will fall below 10 knots overnight while
gradually veering to the northeast. A light and variable wind
around sunrise will become southerly and increase between 5 and 8
knots Wednesday afternoon.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 39 66 50 80 54 / 0 0 0 0 0
Waco 37 70 44 85 53 / 0 0 0 0 0
Paris 32 62 41 76 49 / 0 0 0 0 0
Denton 33 67 45 80 47 / 0 0 0 0 0
McKinney 32 64 45 79 47 / 0 0 0 0 0
Dallas 39 65 49 80 56 / 0 0 0 0 0
Terrell 32 64 43 80 50 / 0 0 0 0 0
Corsicana 37 66 46 81 56 / 0 0 0 0 0
Temple 38 70 45 84 52 / 0 0 0 0 0
Mineral Wells 35 72 45 84 50 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 3 AM to 9 AM CDT Wednesday for TXZ091>095-
104>107-120>123-135-148.
&&
$$
Area Forecast Discussion
National Weather Service North Platte NE
617 PM CDT Tue Oct 18 2022
...UPDATED FOR AVIATION...
.SHORT TERM...(This evening through Wednesday night)
Issued at 313 PM CDT Tue Oct 18 2022
1034 mb high pressure centered over the Red River in the Dakotas
will build south and be centered over OK Wednesday morning, the
Texas coast Wednesday evening, and the upper Gulf coast Thursday
morning. This will open the door for very warm air across the
northwest U.S. to spread east into Nebraska late tonight through
Thursday morning.
The temperature forecast tonight uses the guidance blend and this is
slightly cooler than the NBM 50th percentile. Winds will be light
from the south and west and precipitable water falls to around 0.25
inches by morning. This should be favorable for radiational cooling.
The guidance blend is in place Wednesday for highs in the 60s and
70s. This forecast is warmer than the NBM 50th and supported by
northwest sfc winds and h850mb temperatures around 15C. An upper
level disturbance across Alberta this afternoon will move south and
spread some high clouds across wrn and ncntl Nebraska. The forecast
assumes the effect of these clouds on the heating cycle will be
negligible.
The guidance blend suggested lows in the 30s to around 40 Wednesday
night which is cooler than the NBM 50th or the short term model
blend. The forecast continues to lean on radiational cooling for
support for the cooler lows.
.LONG TERM...(Thursday through Tuesday)
Issued at 313 PM CDT Tue Oct 18 2022
The ECM and GFS now suggest 972-981 mb sfc low pressure will
form near the ND-MN border next Monday. This is a couple hundred
miles south of the predicted position yesterday. The upper level
support has shifted south likewise and the ECM shows the h700mb low
passing over the Black Hills; the GFS is farther north. Rain chances
are still 30-40 percent Sunday into Monday but the ECM is showing
robust wrap around affecting Pine Ridge Sunday; the result of the
southward shift in the dynamics.
The basic forecast philosophy is the same. The models are a little
slower with the arrival of the Pacific front Sunday and this allows
for highs in the 70s along and east of highway 83. The front will be
vigorous, move rapidly east, and produce showers and perhaps an
isolated thunderstorm, given the steepening lapse rates with the
approach of the upper low. The models are suggesting sustained winds
of 30 to 40 mph behind the front and this is consistent with the
deep storm. Our blended forecast uses the NBM 90th percentile for
speeds of 20 to 30 mph Sunday and Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 617 PM CDT Tue Oct 18 2022
VFR will continue through Wednesday evening for western and north
central Nebraska terminals as just a few high clouds stream by.
Winds will be light until midday, then strengthen out of the
northwest.
&&
.FIRE WEATHER...
Issued at 313 PM CDT Tue Oct 18 2022
RH and winds in the RAP model place the Frenchman basin in
Red Flag criteria Wednesday. The blended forecast is very close with
the wind and just a few percent more moist with the humidity. A Fire
Weather Watch is in place for this area.
Two more days of fire concern, Thursday and Saturday. The dry air
Thursday is over the top with 850-500mb RH less than 15 percent and
precipitable water around 0.15 inches. Fortunately, winds will be
light westerly at 10 to 15 mph and the risk of critical fire weather
conditions appears low.
The wind situation Saturday is more favorable with sub 990mb sfc low
pressure across the nrn high Plains setting the stage for south and
southwest winds at 15 to 25 mph. 1000-700mb RH falls to 15 to 20
percent in the GFS. The NBM is already suggesting 15 to 20 percent
sfc humidity and the GFS shows sfc humidity less than 10 percent.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Wednesday afternoon through Wednesday
evening for NEZ210.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Snively
FIRE WEATHER...CDC
Area Forecast Discussion
National Weather Service Pendleton OR
439 PM PDT Tue Oct 18 2022
.UPDATED AVIATION DISCUSSION...
.SHORT TERM...Today through Thursday night...Current satellite
and radar are showing clear skies over the region. There is some
lingering smoke and haze in Central Or and the Wallowas due to the
current fires near those areas. Todays highs are expected to be
in the 70s for much of the region with high 50s to low 60s in the
higher terrains.
The short term models, HRRR/SREF/NAM12 and RAP are in solid
agreement with the upper high still parked over the region. Dry and
above normal temperatures are expected through Thursday. ECMWF EFI
is signaling above seasonal average temperatures for those days.
Expect temperatures to hover in the mid 70s at most locations with
higher terrains seeing 60s through the remainder of the
period.
Beginning Thursday night, the ECMWF/GFS/SREF and the NAM12 are all
in solid agreement that a shortwave disturbance will meander down
the leading edge of the ridge causing the ridge to begin to break
down. WPC Cluster tool is showing the ensembles are in strong
agreement of the breakdown with the only variance being with
position or amplitude of the in coming shortwave. The NAM and the
GFS are both showing that there is a chance of some precipitation
clipping the far northern Washington Cascades Thursday night where
as the ECMWF has it dry. This will begin the ridge breakdown and
lead the region into the beginning of a significant weather change.
Bennese/90
.LONG TERM...FRIDAY THROUGH MONDAY NIGHT... The extended period
is characterized by a major weather pattern change from sunny,
above normal temperatures to a more wet and cool pattern beginning
over the weekend. This change will begin Friday as winds begin to
increase through the early morning hours. Rain chances will
initially begin along the Cascades through the morning, before
spilling across the Basin and through our region Friday afternoon
through Saturday morning. A reinforcing system looks to follow
closely behind on Sunday, returning showers to the forecast area
Sunday into Monday morning. Rain amounts of 1.0-1.5 inches for the
Cascades, Blues, and Wallowas, 0.85-1.1 inches along the east
slopes of the Cascades, 0.50-0.80 inch across Central Oregon and
the foothills of the Blues, and 0.05-0.25 through the Lower
Columbia Basin are expected from Friday afternoon through Sunday
evening. Mountain snow is also likely with this Friday/Saturday
event as snow levels creep down into the 3000-4000 foot range
Saturday night into Sunday. This coincides with the dry slot in-
between systems, but the snow level will free fall from 8000 feet
Friday to 5000 feet early Saturday morning. Snow amounts will
reach 1 to 4 inches across the Cascades, Blues, and Wallowa
mountains, with up to 6 inches possible at higher elevations. The
other sensible weather concern resides with the increased wind
gusts on Saturday as gusts of 40 mph out of the west will be
possible through north-central Oregon, peaking Saturday afternoon.
The ECMWF EFI highlights these climatologically significant wind
gusts through the Eastern Gorge and the east slopes of the Oregon
Cascades on Saturday. The GFS is also picking up on the elevated
winds, as 850mb winds reach the 40-50 mph range through the
aforementioned areas during the same timeframe.
An upper level trough drops from the Gulf of Alaska on Friday as the
axis pushes along the coast by the evening. This will allow for
winds to begin to increase through the morning as showers begin to
spread northwest to southeast across the area. The trough will
continue to dig into Nevada as northwest flow aloft initiates to
provide much cooler temperatures Friday with highs peaking in the
mid to upper 60s through the Basin. Temperatures continue to fall
through the weekend as highs hover in the mid to upper 50s for lower
elevations of the Basin Saturday and Sunday. Temperatures do seem to
increase slightly into Monday as a weak ridge bumps highs back into
the upper 50s to low 60s for the Basin.
Guidance is in good agreement with the overall pattern change and
the dropping upper level trough late Friday. However, differences do
arise with the trough strength and the potential ridging into the
workweek. The ECMWF trough digs slightly deeper and is less broad
than the GFS, and the ridging that occurs behind the system on
Monday is much stronger with the GFS scenario. This relates to a
cooler, windier, and slightly drier outcome with the GFS than the
ECMWF. The 500 mb EOF pattern highlights the main model variability
as being related to the strength of the ridge and the subsequent
timing of its exit. The cluster phase space shows the ECMWF ensemble
members being more tightly grouped and more aligned with the
deterministic outcome than the GFS members. NBM QPF trends have also
continued to increase with each run, adding confidence that rain
amounts may continue to tick upward as the event nears. Thus,
slightly more confidence is in the ECMWF outcome of a deeper, less
broad trough late Friday into Saturday, with less upper level
ridging expected on Monday. 75
&&
.AVIATION...00Z TAFS...Generally VFR conditions are expected
through the TAF period. It`s possible haze from regional wildfires
may briefly drop visibility to MVFR like what`s currently
occurring at PSC. However, outside of the PSC situation which
should see improvement around 03z, any drops should be fairly
brief. Winds stay light and terrain driven. 99
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 40 73 40 75 / 0 0 0 0
ALW 42 73 42 75 / 0 0 0 0
PSC 42 72 41 74 / 0 0 0 0
YKM 40 75 39 75 / 0 0 0 0
HRI 40 74 40 76 / 0 0 0 0
ELN 40 77 41 73 / 0 0 0 0
RDM 35 77 34 78 / 0 0 0 0
LGD 41 76 40 76 / 0 0 0 0
GCD 41 80 40 79 / 0 0 0 0
DLS 45 79 43 78 / 0 0 0 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
SHORT TERM...90
LONG TERM....75
AVIATION...99
Area Forecast Discussion
National Weather Service Phoenix AZ
455 PM MST Tue Oct 18 2022
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
Seasonably warm and dry weather will persist through Friday. An
area of low pressure will arrive across the West from Saturday
into Sunday. Clouds will increase, and there is a chance of rain
showers across Central and Eastern Arizona from late Saturday
through early Monday. Temperatures will turn cooler by the end of
the weekend as a dip in the jet stream overtakes the region.
&&
.DISCUSSION...
High pressure is now fully in control of the weather across
Arizona and California. A broad 500mb ridge axis, with heights
from 580-585 dam, extends from near Glacier NP south to San Diego.
Strong, cool surface high pressure sits over the Great Plains,
extending westward into New Mexico.
The anomalous surface high is bumping against relatively lower
pressures across the Colorado Desert. This will continue to
promote easterly breezes. Already today, we have had a few gusts
over 30 mph along the Gila River Valley. HRRR depicts another
nocturnal 850mb jet (ESE 30-40KT) overnight. This will mix out
early tomorrow, allowing for a few 25-35 mph gusts to reach across
the lower AZ deserts at that time. High terrain locations east of
Phoenix, above 4,000 feet and near our mountain peaks, could
experience brief gusts over 40 mph for a few hours Wednesday
morning. Bumped winds and gusts a bit above NBM deterministic to
account for this.
ACARS soundings out of Sky Harbor exhibit classic characteristics
of an upper high pressure system. A deep layer of dry, subsident
air resides above 700mb. The ridge axis moves little through
Friday. This will continue to provide sunny, warm weather through
the end of the work week. Ensemble-averaged 850mb temperatures
will peak from +19C to +20C Wednesday - Friday. This corresponds
to high temps 88-91F over the lower deserts the next three
afternoons. NBM probability of reaching 90F on Phoenix is 50-60%
Thu/Fri.
We are still tracking a significant pattern change during the
course of the weekend. A 130KT jet streak is forecast to
eventually carve out full-latitude trough over the interior West
by Sunday. A closed low offshore of California will feel the
influence of this trough, pulling it eastward as it either
weakens or becomes absorbed.
Unsurprisingly, a close look at cluster analysis revealed a few
changes from yesterday. More members now show the cut-off feature
lagging the base of the trough. +PW anomalies return for a time,
but this disjointed configuration increases the odds we will have
to rely more solely on northern stream PVA to provide ascent. A
quick comparison of the ensemble suite also shows somewhat less
available CAPE from earlier runs. The timing of the better
moisture is a little later now, centered on Sunday. The best
chance for appreciable rain is still immediately NE of Phoenix.
PoPs are holding relatively steady from before: <10% near the CO
River, 20-30% near Phoenix, 30-50% in Gila County. Drier air
overtakes the pattern beginning Monday, squelching rain chances.
500mb heights fall to near 570 dam Sunday before quickly rising
back to near 580 dam Tuesday. Temps will cool off, but not to the
extent that is expected off to our north. NBM drops MaxT`s for
Phoenix into the upper 70s to low 80s early next week; this would
be 4-7F below normal. More noticeable will be our MinT`s, with
widespread 50s now in the forecast.
&&
.AVIATION...Updated 2345Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
There is good confidence that stiff E flow will persist throughout
the period without the typical W switch on Wed afternoon. Although
wind speeds will be variable tonight and range from light to
periodically moderate and breezy with some gusts upwards of 20 kt
possible. Also late tonight into early Wed morning during the
lighter wind speed periods, some LLWS is likely to develop.
However only at KSDL does guidance favor it meeting criteria as
shown in its TAF. On Wed, winds become mostly breezy again by mid
morning with daytime gusts in the upper teens to upwards of 25 kt.
The strongest gusts are forecast during late morning to early
afternoon and again during the late afternoon to early evening.
skies will be mostly clear with occasional FEW-SCT high decks,
Southeast California/Southwest Arizona including KIPL and KBLH:
No weather concerns should exist through Wed under clear skies.
Confidence is very good that winds will favor mostly light N
component and lgt/vrb at KIPL, with light to moderate N-NE
components at KBLH with breezy NE conditions during the day with
gusts of 15-20 kt. Skies to remain mostly clear.
&&
.FIRE WEATHER...
A warming and drying trend will continue through Thursday. High
temperatures will climb into the low 90s, with minimum RH`s dropping
back into the low 20s percent by Thursday. Cooling temperatures and
moistening conditions going through the weekend will bring minimum
RH`s up into the low to mid 30s by Sunday. Winds expected to be
easterly for the most part 5-10 mph with late morning to early
afternoon breezy conditions through Wednesday across the lower
deserts. Strong easterly gradient 15-25 mph expected in higher
terrain east of the Phoenix metro during this time period. Afternoon
south to southwest favored directions are expected to develop as
early as Thursday.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Heil
AVIATION...Sawtelle
FIRE WEATHER...Young