Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/22
Area Forecast Discussion
National Weather Service Columbia SC
746 PM EST Thu Mar 10 2022
.SYNOPSIS...
A boundary remains over the area with rain showers possible
through the end of the week. A strong cold front and low
pressure system will develop and move through early Saturday,
bringing the risk of severe weather. Windy conditions expected
behind the front Saturday before a major cool down with morning
lows below freezing Sunday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Surface high pressure over the Mid-Atlantic will continue to
direct NE low level winds into the forecast area. Low level
moisture will stay locked in place through the night with
overcast or mostly cloudy skies. Measurable rainfall is unlikely
overnight though, since the deeper moisture has moved out of
the area.
There may be some clearing in the northern Midlands where
moisture will be shallow. If this occurs, the HRRR indicates
that fog may develop near the NC/SC border. Lows will be mild
due to cloud cover and high dewpoints. Expect temperatures
overnight to be in the mid to upper 40s. Some spots in the
northern Midlands may dip into the low 40s if cloud cover
decreases.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Friday: The wedge will continue to influence the weather for the
day on Friday. Low clouds will be firmly entrenched over the
area. The big question is if the in situ wedge breaks Friday
with a large spread among models differing on this solution.
Traditionally the models do not handle the breakdown of the
wedge well and are too quick in the process. Forecast soundings
do appear that the GFS is a bit too eager to mix out the low
clouds but the high pressure is not in a favorable location for
the wedge to continue through the day. However, think it will be
hard to dislodge given the wind direction/speeds through the day
and warm frontal boundary sluggishly moving northward. The
caveat will be that the precipitation will be moving in during
the mid/late portion of the day which could help weaken the
wedge. For now will stay lower than most of the guidance and
keep the wedge in for much of the day.
Friday Night: A strongly amplified trough to the west will begin
to move towards the area. The surface low that developed along
the Gulf Coast will strengthen considerably with an immense
amount of upper divergence courtesy of a 150 knot jet streak.
Strong SW flow will allow PWATs to increase significantly,
approaching the climatological max over the area, comparing to
CHS sounding climo. With 850mb winds increasing to around 60 to
70 knots late and 500mb winds around 85 knots across the area,
there will be plenty of shear to support severe weather as the
surface low tracks through the Upstate and associated cold front
moves through the area. The question will be if storms will be
surface based, which by the nature of the timing of the arrival
of this low, is not climatologically favored. As we start to
enter HiRes model territory there are some concerns working
against instability becoming surface based with convection
depicted in multiple CAMS ongoing across south GA and the FL
panhandle which would limit surface destabilization in our area.
While thunderstorms are likely, at this point they do appear to
be more elevated. The models continue to show a surge of
instability late Friday night/early Saturday morning of CAPE and
LI`s up through the CSRA and into the eastern half of the CWA.
This continues to be a setup worth watching for a conditional
damaging wind gust and tornado threat. Any convection that does
develop will produce downpours, but the speed at which storms
will be moving will limit any flooding concerns. As for
temperatures overnight, expect a gradual rise in temperatures
after midnight as the warm front gets a surge from the
increasing s/sw wind field ahead of the cold front. Expect the
low temperature to occur during the evening hours.
Saturday: Some timing differences among models and the
thunderstorm threat will likely linger into Saturday morning.
Notable for the day is the high will be observed across the area
in the morning as a modified arctic airmass will move in behind
the cold front with strong cold advection. Expect morning
temperatures to be in the upper 50s/lower 60s ahead just prior
to the arrival of the cold front. Tight pressure gradient and
soundings indicate very gusty winds behind the front. The winds
at times on Saturday from mid morning through mid afternoon may
approach wind advisory criteria with strong consensus among
models of at least occasional gusts above 40 mph, especially in
the CSRA. Cold air will continue to funnel into the area into
Saturday night with temperatures expected to drop well below
freezing. Fairly tight spread among SREF members of temperatures
dropping into the 20s across the area. Due to the expect drop
in temperatures due to CAA and weakening wind field a Freeze
Watch has been issued for Saturday night into early Sunday .
Expect temperatures to be in the lower to middle 20s.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
In the long term, there appears to be one more cold morning
across the Midlands and CSRA as high pressure gradually slides
east and off the Carolina coast by Monday morning. Another
Freeze/Frost product may be necessary for Monday morning.
For the remainder of the period, the long term shows limited
spread in temperatures among blended guidance and fairly decent
predictability. High pressure will be over the area and quickly
move offshore as temperatures moderate with EC ensemble mean
supporting a return to zonal flow and weak ridging by the end of
the period. Moisture will begin to return, although there is
quite a bit of uncertainty in the extent with fewer EC ensemble
members quite as bullish compared to the GEFS suite. Relatively
benign weather generally expected through the long term period.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
High confidence in widespread cig restrictions throughout the 24
hr TAF forecast period.
Cold air damming wedge conditions remain in place this evening
with high pressure centered over the Mid-Atlantic ridging into
the Carolinas. Low clouds will remain in place overnight
possibly lowering to IFR/LIFR (already LIFR at DNL). Lower
confidence in vsby forecast and going with prevailing VFR and
tempo down to MVFR but they could drop earlier than forecast and
stay down late tonight into mid morning Friday. Winds will be
light from the northeast to east through the period. Some
diurnal improvement is possible in cigs but confidence is low.
Moisture will increase on Friday as a cold front begins to
approach the area and some drizzle or light rain is expected to
develop by mid afternoon after 20z from south to north with cigs
falling again.
EXTENDED AVIATION OUTLOOK...Periods of ceiling and visibility
restrictions are possible through Saturday morning with deep
moisture in place over the region. Very strong winds expected on
Saturday behind the front.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...Freeze Watch from Saturday evening through Sunday morning for
GAZ040-063>065-077.
SC...Freeze Watch from Saturday evening through Sunday morning for
SCZ016-018-020>022-025>031-035-037-038-041-115-116-
135>137.
&&
$$
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
929 PM CST Thu Mar 10 2022
.UPDATE...
Issued at 929 PM CST Thu Mar 10 2022
Going forecast is in good shape and no changes planned this
evening. The ~150 mile wide band of frontogenetically driven light
to moderate snow continues to blanket all but the far northwest
CWA with light to moderate snow. The band should continue to shift
slowly southeast tonight, with snow tapering off to flurries
before ending from the northwest. Its only been the past hour or
two that we`ve really seen road conditions deteoriorating as
residual pavement warmth took some time to be overcome. Forecast
snowfall amounts look on target with 1-3" likely, mainly southeast
of the I-55 corridor.
- Izzi
&&
.SHORT TERM...
Issued at 253 PM CST Thu Mar 10 2022
Through Friday night...
The going forecast message for tonight`s minor snow event remains
on track. Did move forward the onset time of the steadier snow
and inch up the snowfall amounts a smidge. While temporary
heavier rates -- or at least more than "light" -- are expected,
impacts still look to be on the minor end of the scale, helped by
filtered sunshine earlier this afternoon warming pavement
surfaces. So we continue to opt with just a Special Weather
Statement (SPS) and associated other graphical messaging.
The 100-120 kt upper jet has expanded over the area this
afternoon, with associated broader synoptic scale forcing for
ascent translating overhead. A lead impulse within this flow, as
well as a tightening lower- to mid-level baroclinic zone, has
resulted in a focused area of snow from southeast Iowa into
western Illinois that is moving into north central Illinois as of
230 PM. There is analyzed frontogenesis (f-gen) within the 850 to
700 mb layer correlating with this area, and southerly flow and
WAA at that layer to its south to help sustain this f-gen and
moisture transport into this area. There also is some slightly
negative or near negative values of saturated EPV (instability).
While there is near-surface dry air as evidenced by dew points in
the upper single digits to lower teens, observations and webcams
are starting to show some non-accumulating snow occurring. With
pavement temperatures in the 40s thanks to the earlier filtered
sunshine. this will likely continue to be the case through the
daytime hours on paved surfaces.
Short term models such as the RAP sustain the mid-level f-gen
zone of forcing eastward into the CWA through mid-evening. In
particular, LaSalle, Livingston, Grundy, Will, and Kankakee
Counties, where there is indication of half inch per hour rates at
times through mid evening. The f-gen gradually focuses more east-
southeast in the CWA later this evening into overnight, with a
tapering from northwest to southeast as the mid-level trough
gradually passes late tonight into Friday morning. Lingering light
accumulating snow may be continuing through much of Friday
morning east of I-57.
Immediately on the heels of this system, and part effects from it,
will be a modified arctic front diving southeastward into the
region Friday afternoon. Guidance is in good agreement on the
timing of this during the afternoon with temperatures dropping
behind this into evening. Along the strengthening front itself,
there is focused convergence and steepened low-level lapse rates.
Forecast positive CAPE values are 10-30 J/kg on the RAP with the
cloud layer intersecting the DGZ. This cloud layer is fairly
shallow though, and the focus is moving quickly. It`s possible
some gusty snow showers develop with this setup, especially in
southern Wisconsin ahead of the vorticity maximum center. Did add
some low PoPs for this Friday afternoon.
As the cold air floods in, temperatures will drop into the single
digits to lower teens by early Saturday morning. Wind chills by
Friday mid-evening will be nearing zero, and by early Saturday
morning will have dropped to 0 to 10 below, which is impressive
for March 12. Lake effect clouds and likely at least flurries or
light snow showers are expected into Porter County Friday night,
especially late. Some minor accumulation may occur with these.
MTF
&&
.LONG TERM...
Issued at 301 PM CST Thu Mar 10 2022
Saturday through Thursday...
Main highlights remain the same for the long term:
-Frigid air mass and below zero wind chills overnight Friday into
Saturday.
-Lake effect snow accumulations in Porter Co., IN Saturday morning
ending during the afternoon.
-Warm up coming at the end of the weekend into the workweek.
By 00z Saturday, the main axis of an upper level trough will
begin to depart east of the Great Lakes, sending a strong sfc cold
front and - 20 to -22C 850mb temps down the fetch of Lake
Michigan. Bufkit profiles at Burns Harbor, IN are advertising lake
surface to 850mb delta Ts around 22C, 8-9k ft ELs, and 500-600
J/kg of lake-induced CAPE in the early morning hours on Saturday.
CAMs are depicting convergence bands forming east of Porter
county. As mentioned recently, limited moisture advection within
the cold air mass could limit accumulations. The LES threat ends
come the afternoon as low level winds back and snow pushes
eastward out of the county.
The main story for Saturday will be the subzero wind chills to start
the day, and afternoon wind chills only in the teens. Actual highs
will top out in the mid 20s. The surface high will slide southeast
by Saturday night and a clipper moving through the Canadian Prairie
into the Upper Great Lakes will place Illinois within warm return
flow.
Some guidance is hinting that northern Illinois could be on the far
southern end of snow showers resulting from moderate mid level warm
air advection Saturday night. Previous forecast decision was to keep
PoPs dry but the latest update introduces some slight chances of
snow and maybe just a dusting of accumulation for far northeast
Illinois during the overnight hours.
After a cold Saturday, warmer weather quickly returns. Sunday high
temps will push into the mid 50s behind the surface warm front with
gusty winds veering out of the west. Overall the warming trend next
week looks solid. NBM daytime highs hold steadily in the mid to
upper 50s, making a run towards mid 60s by next Thursday. The
exception would be near the lake on Tuesday where onshore flow will
keep temperatures in the mid 40s. But then another weak wave moving
into the High Plains will again bring southerly flow areawide
Wednesday into Thursday, keeping conditions warmer than normal,
consistent with the CPC 6-10 day guidance, which has confidence in
above normal temperature throughout the Midwest.
As for precip trends, an upper level trough will make its way across
the Midwest on Monday, pushing a weak cold front and northerly wind
shift through the evening. Moisture looks fairly starved, therefore
confidence on seeing measurable precipitation from this event is
low.
BW/Lenning
&&
.AVIATION...
For the 00Z TAFs...
Forecast concerns for the terminals...
*Snow tonight with reduced visibilities and MVFR ceilings
*Winds turning westerly early Friday morning and increasing in
speed Friday afternoon
*VFR ceilings return Friday morning
MVFR ceilings and snow have continued to move into the terminals
this evening with reduced visibilities under 2 SM for most of the
area. Lower visibilities under a mile have also been observed
briefly as heavier bands of snow have moved overhead. The snow and
reduced visibilities will continue into the predawn hours of
Friday morning before drier air moves in aloft and brings the
snowfall to an end. Total snowfall accumulations of 1 to 2 inches
is expected at the Chicago terminals with slightly higher amounts
possible at GYY.
The MVFR ceilings will gradually lift after the snow comes to an
end early Friday morning with VFR conditions prevailing through
the rest of the day on Friday. Guidance does suggest that a few
snow showers/flurries could be possible as the frontal boundary
moves through late Friday afternoon, but confidence is not high
enough to include formal mention in the TAFs at this time.
The northeasterly winds will persist through the evening before
tuning westerly after midnight with light speeds around 5 kts.
Winds will begin to increase in speed Friday morning as the
atmosphere becomes better mixed and begins to pull 20 to 25 kt
gusts down to the surface. These breezy conditions will persist
through the end of the TAF period with winds shifting
northwesterly Friday evening as a frontal boundary pushes through
the area.
Yack
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...LMZ740-LMZ741-LMZ742...noon Friday to
noon Saturday.
Small Craft Advisory...LMZ743-LMZ744-LMZ745...3 PM Friday to 9
PM Saturday.
&&
$$
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Area Forecast Discussion
National Weather Service Melbourne FL
830 PM EST Thu Mar 10 2022
.UPDATE...
...Strong to Severe Storms Possible The Next Two Days...
...Turning Much Colder Saturday Night Behind a Strong Front...
Current...Several late afternoon/early evening updates to adjust
the earlier Severe Thunderstorm Watch and to adjust POPs/Temps
as widespread convection along a larger scale outflow boundary
dropped south across the CWA. The boundary now lies across the
Martin County, and will drop south of the CWA by the top of the
hour, and exit the far southern waters by about 10 PM.
Evening update will remove POPs for the remainder of the night,
except for a small shower/sprinkle threat across the far north
toward sunrise. Both the HRRR and MAV/LAV MOS are more enthused
about low clouds/fog across the north and central tonight. Given
the combination of widespread rain (heavy across many areas, the
rain-cooled air mass in place, and light winds, this seems fairly
reasonable, and as such fog has been added to the grids/ZFP.
&&
.AVIATION...00Z package also hit fog/stratus harder from MLB north
from 09Z-13Z. Heavier rain did fall near the VRB-SUA corridor, so
may need some AMDs down that was as well. For Fri, slightly lower
POPs, and thus confidence in needing TEMPO TS across the northern
aerodromes is a little lower. If so, best chance would be LEE-DAB,
possibly SFB. But for now, went with VCTS ISM-MCO-TIX northward
and left it out for MLB-SUA.
&&
.MARINE...Passage of large scale convective outflow boundary and
associated storms has made for rather chaotic winds, which shifted
form south to north, and are now in the process of veering back
around to E-SE. We should see these eventually veer back southerly
after midnight, with speeds decreasing below 15kt. Seas 3-4ft.
&&
Cristaldi/Rodriguez
&&
.PREV DISCUSSION... (Issued 355 PM EST Thu Mar 10 2022)
Friday...Stalled frontal boundary lingers north of the area, and may
shift slightly northward as a warm front. Passing disturbances and
lingering moisture will continue an unsettled pattern, with
scattered showers and storms developing into the afternoon across
north central FL and toward the east coast. PoPs range from 50-60
percent north of Orlando and 30-40 percent from around Orlando area
southward through much of the Treasure Coast. Strong to isolated
severe storms will continue to be possible with any convection that
develops. Highs will continue to reach the 80s and possibly around
90 degrees across southern portions of the interior.
Saturday-Sat Night...Unsettled and disturbed weather will
continue into Saturday, which looks to be the most active day this
week. A deep mid level low and associated trough will dig across
the Great Lakes region and down the Mississippi Valley late Friday
night, dragging a very strong cold front towards the FL
peninsula. By 7am, models are in good agreement with the line of
thunderstorms ahead of the front positioned across the FL
Panhandle, with the line reaching the doorstep of Lake and Volusia
counties by late morning to midday. This is a few hours slower
than previously advertised, but the forecast will continue to be
refined in terms of timing once confidence increases. With a
slower arrival time, the front will take a bit longer to sweep
through the area, with models reflecting a position over the
Treasure Coast just prior to sunset.
The threat for severe weather associated with this line continues to
increase, with SPC maintaining a "Slight Risk" across most of the
east central FL area on Saturday, with the Treasure Coast and
Okeechobee County covered under a "Marginal Risk". So far,
instability and forcing appears to be the greatest during the
morning hours, depleting through the afternoon, so timing of the
line becomes increasingly important if storms can tap into peak
ingredients. A potent wind field at the surface into the mid levels
could lead to damaging wind gusts of 60 mph, with a bit of low level
shear aiding in the development of a brief tornado or two,
especially for areas along and north of I-4, although severe weather
will be possible across the entire area as the front passes. Temps
at 500mb not incredibly impressive, so hail will not be as great of
a threat but still could be present with growth of storm tops. As
mentioned, there still lies quite a bit of uncertainty with the
evolution of the event on Saturday, mainly stemming from timing of
the frontal passage, but all of east central FL should be prepared
for strong to severe thunderstorms capable of producing damaging
winds, hail, and brief tornadoes.
For now, will clear most rain chances from the forecast after
sunset, but a few lingering showers and storms could persist across
the Treasure Coast if the line lags according to model trends.
Behind the front, breezy southwest winds will veer quickly to the
west northwest, maintaining speeds of 15-20 mph into the late
afternoon and early evening hours. Highs on Saturday will reach the
mid to upper 70s across the north and climb to the low to mid 80s
south of Orlando.
Dry air will move in rapidly behind the front, dropping PW values to
a measly 0.10", hence the zero rain chances after 8pm Saturday
night. Dewpoints will fall, and with much cooler air arriving
alongside the dryness, temperatures will also fall well below normal
values. Coldest locations will be across northern Lake and Volusia
counties which will drop to 34-35F, then warming a few degrees
progressing southward, to 38-40 from Osceola to coastal Volusia and
the low/mid 40s for the Space Coast and Okeechobee County and the
upper 40s/low 50s along the Treasure Coast. Northwest winds will
remain above 10 mph overnight, which will lead to wind chill
readings in the upper 20s/low 30s in coldest locations and the mid
30s elsewhere.
Extended...(previous) The chilly post frontal cooldown Sunday wl be
somewhat short-lived as temperatures slowly moderate early in the
week. Dry and cool Sunday with highs in the 60s to be followed by
lows in the 40s to around 50 degrees Sunday night, as onshore winds
begin to develop. By Mon aftn a small chc of showers return to the
marine area with further moderation of temps in continuing onshore
flow conditions. Another approaching Gulf system is advertised
around Tue and rain chcs have consequently been bumped up to sct
coverage Tue into Wed at this early juncture. Highs will reach well
into the 70s to L80s by Tue into Wed.
&&
.MARINE...
Friday-Friday night...After diminishing overnight, south winds
increase back to 15-20 knots, with seas 3-4 feet. Showers/storms
expected to be confined to the northern waters much of the day.
Saturday...Hazardous marine conditions will arrive this weekend
as a strong cold front sweeps across the Atlantic waters on
Saturday. Prior to the front`s arrival, the pressure gradient will
significantly tighten, increasing south to southwest winds late
Friday to near 20 knots, further increasing to 25-30 knots by
Saturday afternoon. Winds will begin to veer west and then
northwesterly towards the evening as the front moves through late
in the day. A line of strong to severe thunderstorms is forecast
to push ahead of the boundary, bringing damaging wind gusts,
frequent lightning, locally higher seas and waterspouts across the
Atlantic waters late Sat morning through the late afternoon. Seas
will build from 4-6 ft in the morning to 8-11 ft overnight. At
least SCA headlines will be necessary this weekend, with possible
gale force conditions.
Sunday-Monday...Marine conditions will remain hazardous early next
week as the front pulls away and high pressure builds over the
southeast US. North winds veer northeast on Sunday diminishing below
20 knots by the afternoon as seas slowly fall from 8-11 ft in the
Gulf Stream to 5-9 ft. Conditions will continue to improve into
Monday but still remain poor, with east winds 15-20 knots and seas 4-
6 ft.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 64 82 66 77 / 30 60 30 90
MCO 67 89 69 80 / 30 40 20 90
MLB 66 86 70 83 / 40 40 20 90
VRB 65 87 69 84 / 40 40 20 80
LEE 67 85 69 77 / 30 50 20 90
SFB 66 86 68 79 / 30 50 20 90
ORL 68 88 70 80 / 30 50 20 90
FPR 65 86 69 85 / 40 30 10 80
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
517 PM MST Thu Mar 10 2022
.UPDATE...Updated 00Z Aviation Discussion.
.SYNOPSIS...
A mostly dry weather system will move through the region from this
afternoon to tonight bringing windy conditions to the area,
especially across southeast California and southwest Arizona where
blowing dust is a concern. Isolated to scattered light showers
should also accompany this system, although with the better
chances across the high country north and east of Phoenix. Dry
conditions under mostly clear skies will then prevail into the
weekend through the first half of next week with high temperatures
climbing back well into the eighties by early next week.
&&
.DISCUSSION...
The upper air analysis features a long positively tilted short-wave
trough axis with PVA anomalies extending from the Great Basin and
dropping into S CA, with strong zonal flow across our area just
ahead of the system. The WV image shows the main enhanced moisture
plume of the system to the NE ejecting through the S Rockies. This
also coincided with areas of light precip returns on early afternoon
radar across the N half of AZ. The IR satellite imagery shows the
large cloud shield of the system collocated with the systems main
moisture plume to the NE of the area with clear to partly cloudy
skies lingering over our area. Visible and other satellite imagery
also showed some blowing dust channels beginning to appear in E
Riverside cnty crossing I-10.
The dryish shortwave weather system drops through the region from
this afternoon and well into tonight, with a strong surface high
pressure area building to the north. The tightening gradient has
already begun to generate very strong, gusty northerly wind
conditions in parts of SE CA and SW AZ. With max advisory level
forecast wind gusts of 40-50 mph with, and behind the cold front,
the threat of blowing dust will continue to be very likely in those
areas through this evening. The advisories also includes JTNP and
the Lower CO River Valley. In addition, very breezy conditions will
also spread east into Phoenix and the lower deserts from this
afternoon and evening into tonight, with the higher gusts up to 25-
35 mph in these areas.
The chances of modest amounts of isolated-scattered light rain and
showers across Phoenix and over the high terrain this evening and
tonight have decreased a bit since yesterday. This still includes
some light snow over our high terrain east of Phoenix above ~5-6
Kft. The NBM and ensembles now favor <0.03" of rain for the Phoenix
Metro area and <0.5" of snow for the highest elevations to the east.
The favored NBM POPs/PPIs have now lowered to a fleeting 9-30% after
00Z Fri (Thu evening) for the greater Phoenix area, and 30-40% for
the eastern high terrain near Globe for this evening and tonight. A
very small amount of MU/SBCAPE is still in the mix as models and NBM
hold on to the non-zero, <5% chances for isolated evening
thunderstorms and convection.
The Grand Ensemble and NBM are in good agreement on sufficient cold
air with this system to keep temperatures in a fairly limited range
through tomorrow as the system ejects east. They are also in very
good agreement on a warm-up starting this weekend into early next
week as a strong high pressure anomaly builds in by Sat across the W
CONUS. After a temporary flattening of the ridge on Sun,
ensembles also favor reinforcing high pressure on Mon-Tue with
highs punching well into the 80s early next week. Currently the
warmest day is still forecast for Tue with highs in the mid-upper
80s. The NBM probability of a high of at least 90 degrees for
next Tuesday has fallen to 42% today, down from 52% yesterday.
&&
.AVIATION...Updated at 0017Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Current gusty westerly winds will continue to increase through the
early evening as a cold front pushes through the region. Gusts will
generally remain between 20-30 kts but a few brief gusts around 35
kts can`t be ruled out. The HRRR now shows ~45% chance of gusts
reaching or exceeding 30 kts this evening. Some areas of blowing
dust could potentially impact slantwise visibilities and potentially
surface visibilities, though they should remain above 5-6SM. Gusts
will weaken and taper off going through the latter part of the
evening after FROPA. Could see some LLWS issues at some of the
terminals, but expect this to remain below TAF thresholds. Westerly
winds are expected to continue through most of tonight, then turn
northeasterly towards morning. These northeasterly winds (8-10kts
with gusts as high as 15 kts) are then expected top continue into
the mid-late afternoon hours before becoming more typical westerly
during the late afternoon/early evening hours on Friday. A return to
more familiar diurnal easterly winds is then anticipated by late
evening on Friday.
Aside from the winds, rain chances are low (< 20%) with the best
chances favored to remain over the high terrain north and east of
the metro today. If any virga/light showers do develop near the
terminals, expect little to no rainfall to reach the ground with
gusty erratic winds possible. FEW-SCT clouds aoa 7-9 kft will
continue through the evening before drier air pushes in during the
overnight hours and promotes clear skies.
Southeast California/Southwest Arizona including KIPL and KBLH:
Current very strong gusty winds across the region are expected to
persist well into the evening hours before diminishing
around/shortly after midnight. Northerly gusts could reach as high
as 35-45 kts at KBLH this evening while winds at KIPL are expected
to be weaker. As a result of the strong winds, areas of blowing dust
will be possible, particularly near KBLH, which may drop
visibilities down to around 1 SM at times, and create slant-range
visibility issues as well.
WInds are expected to continue to gradually subside late
tonight/Friday at KIPL. Winds will likely increase for a time again
at KBLH during the early/mid-morning hours on Friday as northerly
winds aloft increase, with LLWS concerns also becoming a
possibility, before winds finally subsiding for good during the late
morning/afternoon hours on Friday. Otherwise, FEW clouds will remain
aoa 9 kft during the period.
&&
.FIRE WEATHER...
Saturday through Wednesday:
High pressure will strengthen over the region into early next week
leading to a strong warming trend and continued dry
conditions. High temperatures will warm from near normal on
Saturday to 9-12 degrees above normal by Tuesday. Winds through
the bulk of the period will be fairly light, but some breeziness
is likely on Sunday and Wednesday. Low humidities will prevail
each day with minimum readings mostly between 7-12% each day,
while overnight readings generally only recover to between 20-40%.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Blowing Dust Advisory until 2 AM MST Friday for AZZ530-531-533.
Wind Advisory until 2 AM MST Friday for AZZ530-531-533.
Blowing Dust Advisory until 10 PM MST this evening for AZZ532.
Wind Advisory until 10 PM MST this evening for AZZ532.
CA...Wind Advisory until 10 PM PST this evening for CAZ560-561-568.
Blowing Dust Advisory until 1 AM PST Friday for CAZ564-569-570.
Wind Advisory until 1 AM PST Friday for CAZ564-569-570.
Blowing Dust Advisory until 10 PM PST this evening for CAZ561-
568.
Blowing Dust Advisory until 9 PM PST this evening for CAZ563-565-
567.
Wind Advisory until 9 PM PST this evening for CAZ563-565-567.
&&
$$
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DISCUSSION...Sawtelle
AVIATION...Percha/Smith
FIRE WEATHER...Kuhlman
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
932 PM EST Thu Mar 10 2022
.SYNOPSIS...
A wedge of cooler air will remain across North Carolina tonight into
Friday. A strong cold front will then cross the region late Friday
night and early Saturday. High pressure will then build into the
region for the end of the weekend, resulting in colder and drier
weather Sunday and Monday.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 930 PM Thursday...
Aside from some lingering spotty light drizzle over the Coastal
Plain, the rest of the night should largely be dry. Low clouds have
lifted/scattered over the northern Piedmont, generally along and
north of I-85. Although high clouds remain, this decrease in cloud
coverage, combined with winds becoming calm as the surface high sits
over the southern mid-Atlantic through tonight. The last few runs of
the HRRR show fog developing over the northern Piedmont late tonight
and lingering through early Friday morning. Should the fog develop,
it could become dense. Elsewhere, low clouds will persist through
tonight. As for temperatures, where the low clouds have scattered
out and if the high clouds break apart, the temperature could drop
into the mid 30s, otherwise elsewhere upper 30s to low 40s are
expected. -KC
Friday will be a difficult forecast as guidance is inconsistent on
how quickly to erode the CAD leading to a 10 to 15 degree spread in
high temperatures. The NAM is more persistent with keeping the CAD
wedge in place through a majority of the day on Friday, while
GFS/ECMWF quickly erode the wedge Friday morning and raise
temperatures well into the mid/upper 60s. Since the NAM is usually
superior with CAD, this forecast package will err on the side of
cooler guidance. However, temperatures Friday could be even cooler
than the current forecast if this solution verifies. Showers will
start to move in from SC as deep WAA begin to overspread the area
ahead of the approaching cold front. -Swiggett
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
As of 330 PM Thursday...
While showers will increase from the south Friday evening as the
wedge boundary moves north, rain chances will dramatically rise as a
cold front approaches from the west. A wave of low pressure will be
somewhere along the front across north-central North Carolina around
sunrise Saturday, and that has resulted in an uptick for the amount
of precipitation forecast in the Triad late Friday night. Rainfall
amounts are expected to be around an inch areawide. Have slightly
expanded the chance for thunder, now covering all but the
northwesternmost portions of the forecast area. While much of the
forecast area is under a marginal risk for severe weather Friday
night, particularly after midnight, a low-level inversion will limit
the amount of available instability for thunderstorms and should
limit the overall severe weather threat. However, SPC has issued a
slight risk for severe thunderstorms generally east of the US-1
corridor for Saturday, and the addition of some surface-based
instability after sunrise should allow for a greater threat of
severe weather during the daytime hours. There will be some modest
speed and directional wind shear in the low levels as well.
Temperatures will follow a non-diurnal cycle, with temperatures
remaining steady or slowly rising Friday night. On Saturday,
temperatures will fall through the day in the west, while remaining
nearly steady in the east during the morning then falling through
the afternoon. It appears that precipitation will move east before
colder air arrives, but a rogue snowflake cannot be ruled out as
precipitation comes to an end. That being said, it has been several
days since temperatures were below freezing, so no snowfall
accumulation is expected. Finally, wind will increase in advance of
the cold front, with gusts up to 20-25 mph overnight and widespread
gusts of 30-40 mph behind the cold front Saturday afternoon.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
As of 330 PM Thursday...
The strong cold front Saturday night moves offshore into the western
Atlantic into Sunday morning as the mid-level trough tracks into the
north-central Atlantic. Behind it, a 1032 mb cold high pressure
settles across the deep south. Immediately behind the front, a tight
pressure gradient will remain, with the departing low pressure
system tied to the cold front and high pressure over northern MS. In
addition to the tight pressure gradient, strong low-level 925 mb
winds of 30-35 kts with the cold air advection will result in rather
gusty northwest winds between 30-40 mph, especially in the early to
late evening hours. With temperatures tumbling to a hard freeze into
the upper teens to lower 20s for overnight lows (15-20 degrees below
normal), wind chills will be in the low to upper teens, making for a
much colder night that what has been experienced lately. Although we
have not reached the peak growing season, it might be a good idea to
bring in potted plants. As high pressure settles across the deep
south early Sunday, winds should decrease toward sunrise Sunday.
Weak mid-level ridging will start to develop on Sunday afternoon and
the surface high will shift toward the southeast coast of NC by
evening. With the cold airmass in place, highs will remain 10-
12 degrees below average in the upper 40s to lower 50s.
Mon-Thu: A gradual warming trend will take place during this period,
as high pressure off the coast of NC shifts east toward Bermuda.
Highs will be some 5-10 degrees above normal in the low to middle
60s Monday to the upper 60s to lower 70s Tue-Thu. Aloft, ridging
will be in place through Monday. The subtropical jet will be active
in the Tue-Thu period. With the southern stream jet, a mid-level
trough is forecast to track from Colorado Sunday night into TX/OK by
Tuesday and become closed off from the main flow. There remains some
uncertainty in the timing and track of this closed mid-level system.
The GFS and NAEFS are faster, bringing the system across the area
Wed-early Thursday, while the ECMWF/CMC and the previous Euro
ensemble are slower, bringing the system in Wednesday night to late
Thursday night. Have kept low-end PoPs late Tue and Wed, then chance
PoPs on Thursday.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 700 PM Thursday...
24 hour TAF period: Fairly confident sub-VFR conditions will persist
and/or develop this evening and tonight. Of lower confidence is how
low the visbys will get and how expansive they will be. There is a
strong signal for fog to develop near the VA/NC border and spread
south and southeastward over KGSO, KINT and KRDU after midnight.
Where the lower cigs (MVFR/IFR) hold on (KFAY and KRWI) the visbys
may not drop as low, but conditions will be sub-VFR nonetheless.
Winds should become calm to light and variable through tonight. Sub-
VFR conditions may linger through much of the morning, gradually
improving back to VFR late Friday morning into Friday afternoon.
Winds should become southerly at 5-10 kts Friday afternoon. -KC
Looking ahead: A strong cold front will bring restrictions in
showers and isolated thunderstorms Friday night into Saturday
morning. While showers and restrictions will come to an end Saturday
afternoon, strong winds are expected out of the south Friday night
and veering to the west Saturday with winds up to 40 mph. Winds will
settle down Saturday night, and dry weather is expected Sunday and
Monday before a slight chance of rain returns on Tuesday. -Green
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Green
NEAR TERM...KC/Swiggett
SHORT TERM...Green
LONG TERM...Kren
AVIATION...KC/Green