Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/01/22
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
719 PM CDT Sat Apr 30 2022
.AVIATION...00Z TAFs
Frontal boundary has moved south into the Hill Country but looks
to have stalled and will drift northward during the overnight
hours. Low level flow will be weaker than previous nights with
southerly winds up to 20 knots. Scattered to broken cumulus/VFR
conditions early this evening with MVFR ceilings expected to
affect coastal regions by 04Z Sunday. These lower ceilings will
gradually spread inland and reach LRD area by 08Z. SREF
probabilities along with the HRRR show ceilings will likely lower
to IFR over the inland coastal plains from 07-08Z with MVFR vsbys
in fog through 14-15Z Sunday. MVFR ceilings will be prevalent
elsewhere until 17Z for the coastal plains and a little later for
the Brush Country. A few light showers could affect the Brush
Country Sunday morning also. VFR conditions will occur through the
rest of the afternoon with gusty southeast winds.
&&
.PREV DISCUSSION... /Issued 326 PM CDT Sat Apr 30 2022/
SHORT TERM (Tonight through Sunday Night)...
A boundary has pushed into the area this afternoon, stretching at
time of writing from around Laredo to around Corpus Christi. The
boundary hasn`t has much impact on our sensible weather, but has
been a focus for just a few small showers mainly near the coast
and offshore. Dont expect much out of this at the boundary
continues to sink southward. Will have to keep an eye out though
to the west for any potential mountain convection that develops
this evening and into tonight. While convection will likely stay
pretty close to the cold front draped across Central Texas,
850-300mb thickness contours tonight are aligned more northwest to
southeast and could bring some convection down into the area.
That said...only the FV3 meso model is really showing this
scenario...other models either keep it along the front or far west
of our area. Will carry some 20 PoPs west into the night for the
small chance here.
By tomorrow, a weak upper shortwave is progressing across the
area, and with PWAT values at or above 1.5" the energy could be
enough to trigger a few showers during the day. Will just stick
with mainly 20 PoPs through the day though as the wave is pretty
weak. A stronger wave will move mainly north of the area by
tomorrow night, and could be a concern for showers and storms
though the best chance will once again be north of the area as
strong storms are expected to develop over West Texas ahead of a
dry line, then push east in the late evening and overnight.
Expect a mainly easterly movement, but can`t rule out some storms
moving or developing into our northwest counties.
Min temps continue elevated tonight and tomorrow night with
abundant low level moisture. Expect lows mainly in the lower to
mid 70s. Despite expected cloud cover, high temps tomorrow should
reach into the lower 90s west and mid to upper 80s east.
LONG TERM (Monday through Saturday)...
Not too much change to the forecast for the upcoming week with
continued breezy/windy, humid and hot conditions persisting. Models
continue show a quasi-zonal flow aloft with upper low pressure
systems remaining north of the region and high pressure remaining
across Mexico well south of TX through mid week. Embedded short
waves in the flow aloft are progged to bring isolated to scattered
showers and thunderstorms into S TX Monday and again Wednesday
night. By the latter part of the week, models indicate a mid/upper
long wave trough digging southeastward across northern Mexico with
the overall synoptic pattern becoming more amplified by
Thursday/Friday and bringing additional rain chances to S TX.
A short wave Monday morning will bring a chance of convection to the
western half of S TX then dries out from west to east through Monday
afternoon as weak ridging builds in behind the short wave. Tuesday
looks rain free, humid and hot with heat indices around 105 across
the Brush Country/Rio Grande Plains. Heat indices could reach 105
briefly each afternoon through the latter part of the week.
As low pressure in the mid/upper levels moves across northern
Mexico, an associated frontal boundary is progged to move across
South Central TX Thursday with models indicating convection ahead
and along the bdry. Models have been inconsistent from run to run
and with each other with this feature. Some runs have brought the
boundary into S TX either Thu, Fri or Sat or stall it north of the
area before it retreats and washes out by the end the week. Given a
southwest flow aloft ahead of the approaching long wave trough, feel
the frontal boundary will not make it to S TX. That being said, an
outflow boundary from convection farther north could move into S TX.
Kept with the National Blend which shows increasing rain chances
beginning Wed night into Thu across the western CWA then shows a
slight chance across S TX Thu night through Fri night. The NBM progs
the surface winds across S TX to back briefly to the east by Sat
with no definitive boundary in the area.
P-ETSS continues to forecast above normal tides through the period
with water levels possibly reaching the dunes during times of high
tide. Tide level trends will continue to be monitored for the
potential for minor coastal flooding.
MARINE...
A mainly moderate onshore flow will persist tonight through Sunday
night before increasing to more moderate to strong levels Sunday
night. Moderate to strong onshore flow will persist through the
week with advisory conditions possible at times. Isolated showers
and thunderstorms are possible toward the end of next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 74 87 75 87 75 / 10 10 10 10 10
Victoria 71 88 73 87 72 / 10 10 10 10 10
Laredo 74 93 75 95 74 / 10 20 30 20 0
Alice 73 90 74 92 73 / 10 10 20 20 10
Rockport 75 84 76 85 76 / 10 10 10 10 10
Cotulla 72 92 73 92 74 / 20 30 40 40 10
Kingsville 74 89 75 90 74 / 10 10 20 10 10
Navy Corpus 75 83 75 82 76 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
TMT/89...AVIATION
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
644 PM CDT Sat Apr 30 2022
...New AVIATION...
.SHORT TERM...
(Tonight through Sunday night)
Issued at 132 PM CDT Sat Apr 30 2022
Two different weather features will drive the weather in the short
term. The first of these is a cold front currently located from south
of Rocksprings to Kerrville to Blanco to Georgetown. A prefrontal
boundary moved through the morning and helped clear out much of the
cloud cover a bit earlier than expected. The front itself had been
making decent progress to the south and east through the morning, but
has finally begun to slow down as expected. Most of the mesoscale
models show the front becoming stationary very near where it is
currently located before lifting back to the north late tonight. Some
showers have already tried and failed to develop across Bell County
to our north and additional showers and storms are expected this
afternoon thanks to the ample heating the area is now seeing. The
HRRR, depending on the run has shown isolated showers and
thunderstorms along the whole length of the front in our area from
the Rio Grande right through the Austin Metro area. This is supported
by other models, with some like the Texas Tech WRF, lingering showers
and storms late into the overnight in areas like Williamson and Lee
Counties. In addition, the Texas Tech WRF and one or two of the other
mesoscale models show additional shower and possibly thunderstorm
activity across parts of the Rio Grande Plains overnight. Have lower
confidence in this activity, but have maintained a 20 PoP out west to
cover the chance given that the NBM picked up on this activity as
well. Any storms that do develop this afternoon have a chance to
become strong to severe. While shear is limited, which will likely
lead to more pulse type convection (a storm forms, strengthens, then
dies), there is plenty of CAPE around with anywhere between 1500 j/KG
to 2500 j/KG along with fair lapse rates around 7 C/km. Large hail
will be the primary hazard, with damaging winds secondary. One note,
the HRRR does depict some afternoon development along the Serranias
del Burro mountains later today. Typically when upper flow is more
zonal and weak, like it is today, these storms tend to take a hard
right turn and stay in Mexico. It may be a different story on Sunday.
SPC has a band of Marginal Risk area across much of our CWA ahead of
the surface boundary to account for the severe risk.
As mentioned above the front draped across our area this afternoon
will lift back north overnight as a warm front allowing Gulf moisture
to surge northward. Some isolated showers/drizzle may be ongoing
Sunday morning especially across parts of the Hill Country and Rio
Grande Plains. By late in the day an upper level shortwave will
approach West Texas and begin to interact with the dryline to produce
thunderstorms from the Texas Panhandle down to the Big Bend. Storms
should be firing in these areas west of Val Verde county by 4pm, with
the activity working eastward by 6pm lasting into the overnight
hours. Models show a bit of a mixed solution with how storms will
evolve overnight. Most keep activity confined to Val Verde County and
close to the Rio Grande, while a few (notably the NSSL WRF) bring a
few isolated storms close to the HWY 281 corridor during the
overnight hours Sunday into Monday morning. The best atmosphere will
be along the Rio Grande and across West Texas where similar CAPE and
lapse rates to today will be met with better shear (40-50 knots
worth) which should help sustain storms longer tomorrow. There may
also be some Serranias del Burro supercells again tomorrow, and with
the upper flow turning more out of the southwest and increasing
ahead of the main trough they should have a better chance at crossing
into Kinney and Maverick counties late in the day. Models do show
convective parameters decreasing the further east towards HWY 281 and
I-35 corridor which supports the SPC updates to the convective
outlook for their Day 2 which highlights Val Verde county with a
Slight Risk, and generally a line from Leakey to Uvalde to Eagle Pass
westward with a Marginal risk.
Any storms that do form could produce a quick downpour either
Saturday or Sunday with some areas picking up a quick 1/3 to 1 inch
of precipitation while most of the rest of the area remains dry.
Afternoon highs will range from the low 80s to near 90 each day -
cooler where cloud cover sticks around and warmer in places that see
more sunshine.
&&
.LONG TERM...
(Monday through Friday)
Issued at 132 PM CDT Sat Apr 30 2022
Our stretch of active weather will look to continue into the month
of May as several key features act to focus showers and scattered
thunderstorms over the CWA this week.
On Monday, remnant showers and thunderstorms from overnight
convection may be moving through the CWA, generally from west to
east by midday then through the eastern zones by mid afternoon. At
this time, severe storms are not anticipated but SPC does have a Day
3 Marginal Risk for portions of the Southern Edwards Plateau and the
western Hill Country. Primary threats would be large hail and
damaging winds, but the threat appears to be highly conditional at
this time. Once the 500mb shortwave moves through Monday afternoon,
we should remain under largely west-southwesterly mid-level flow
into the day on Tuesday.
Our next weather maker should arrive by midweek, Wednesday/Thursday,
as an upper-level low deepens over the central Rockies. This will
act to send at least one and maybe even a couple of shortwave
disturbances through South-Central Texas Wednesday and Thursday.
Wednesday may provide the best threat for scattered thunderstorms as
the southern branch of the 300mb jet sets up over central Texas,
placing much of South-Central Texas within the favorable right
entrance region. Model forecast soundings indicate rich boundary
layer moisture with dewpoints surging into the mid to upper 60s and
even some lower 70s sprinkled in over the Coastal Plains on
Wednesday. One item of note is the very steep mid-level lapse rates
depicted by the GFS Wednesday evening, which would be quite
favorable for a severe threat, given modest instability and
favorable deep-layer shear over the Hill Country and the Rio Grande
Plains (30-50 kts). One more item of note is the fairly high PWATs
that will be in place over much of the area by midweek. If storms
can grow upscale, locally heavy rainfall is possible. Obviously,
we`ll take pretty much anything we can get at this point, as much of
the region remains within D2 to D4 drought.
Beyond Thursday, the region may transition into a bit of a
northwesterly flow regime, but models differ on the evolution of the
pattern at this time. We should be able to keep rain chances in the
forecast though through much of this upcoming week.
&&
.AVIATION...
(00Z TAFS)
Issued at 629 PM CDT Sat Apr 30 2022
VFR conditions persist this evening as the front remains north of
the aerodrome sites across the Hill Country and Southern Edwards
Plateau. Isolated convection remains possible along the front but
areal coverage and confidence is too low for inserting any VCTS
within the TAF package at this time. The front lifts northward as
a warm front overnight where some showers and isolated storm may
also occur with the low-level moisture advection. Elected to keep
VCSH in KAUS and KDRT where the greatest chance exists for any
activity into and through the overnight. MVFR to IFR ceilings are
expected to develop overnight and will continue through much of
Sunday afternoon before improving to VFR levels into and through
the afternoon hours. Isolated to scattered convection possible
Sunday afternoon but confidence remains too low for VCSH or VCTS
mentions.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 69 87 70 85 / 20 20 30 40
Austin Bergstrom Intl Airport 68 87 70 86 / 20 20 20 40
New Braunfels Muni Airport 69 87 71 87 / 20 20 20 30
Burnet Muni Airport 66 85 69 83 / 20 30 30 50
Del Rio Intl Airport 72 86 72 91 / 30 30 50 30
Georgetown Muni Airport 66 86 70 85 / 30 30 20 40
Hondo Muni Airport 69 89 71 87 / 20 20 40 50
San Marcos Muni Airport 69 87 70 86 / 20 20 20 30
La Grange - Fayette Regional 70 87 72 88 / 20 20 10 20
San Antonio Intl Airport 70 87 71 84 / 10 20 30 40
Stinson Muni Airport 72 89 73 89 / 10 20 30 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...Treadway
Long-Term...Morris
Aviation...Brady
Area Forecast Discussion
National Weather Service North Platte NE
626 PM CDT Sat Apr 30 2022
.SHORT TERM...(This evening through Monday)
Issued at 252 PM CDT Sat Apr 30 2022
All remaining precipitation has moved out of north central
Nebraska this afternoon as the low pressure system becomes
centered over Minnesota and Wisconsin and wrap around moisture
becomes too far out of reach for central Nebraska. The tight
pressure gradient will ease this afternoon and evening as the low
moves out and high pressure begins to build in from the west. This
will lead to a decrease in strong northwesterly winds starting in
the Panhandle and moving east into north central Nebraska. Bufkit
soundings along with the HRRR and NAMNST wind gusts show a
decrease in strong wind gusts after sunset. Have decided to end
the High Wind Warning at 03Z. Otherwise, mostly quiet weather is
expected tonight with lows in the 30s. Some CAA may occur as
northwesterly flow will continue on the far west side of the low
pressure system, so used NBM 25th percentile for low temperatures
tonight.
Mild weather is on tap for Sunday as ridging develops over the Great
Plains before the next disturbance moves east across the Rockies.
Temperatures range from the upper 50s in northern Nebraska to the
upper 60s in southwest Nebraska; about normal to the south, but
below normal to the north. Low temperatures Sunday night will be in
the 30s, with the coldest temperatures along the Pine Ridge. The
weather pattern begins to change on Sunday night as the upper level
disturbance advects across the Rockies and brings the next
opportunity for precipitation. This is mainly expected to be in the
form of rain, but some areas of the Panhandle and Sandhills may
receive snowfall or a rain/snow mix. Some thunder cannot be ruled
out either on Monday, especially in southwest Nebraska where
there is more instability.
There remains a discrepancy between models for snow amounts and
location for Monday. The European Model, NAM, and NAMNST seem to set
up a deformation band and accumulating snow over the Sandhills
during the day on Monday. Soundings show sufficient lift in the
dendritic growth zone. Dynamic cooling earlier in the day might keep
temperatures cool enough for some accumulation but warmer
temperatures at the surface may be a limiting factor for
accumulating snowfall. Meanwhile, the GFS suggests snow along and
east of the Pine Ridge on Monday morning. Elevation will help
maintain cooler temperatures and snowfall. With both solutions this
will be a heavy, wet snow likely mixed with rainfall much of the
time. Snow ratios will be less than 10:1. Will continue to monitor
for location and amounts for snowfall.
.LONG TERM...(Monday Night through Saturday)
Issued at 252 PM CDT Sat Apr 30 2022
Precipitation will move east out of the forecast area on Monday
night as the upper low moves east out of the area. Temperatures will
be below normal on Tuesday with highs in the upper 40s to mid 50s.
That being said, the amount of snowfall that remains from the
previous system may help lower temperatures in some areas. Once
again, another upper level disturbance will move out of the Rockies
and into the Great Plains on Tuesday night into Wednesday, bringing
more opportunities for precipitation. A rain/snow mix may occur
early on Wednesday on the Pine Ridge, and thunder is possible in the
afternoon and evening. The possibility for rain and thunderstorms
appears to continue through the end of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 619 PM CDT Sat Apr 30 2022
VFR conditions will persist through the forecast period. Strong
northwest winds will gradually diminish through late evening.
Expect winds to veer to northeast by early afternoon Sunday while
remaining generally light though a gust of near 20 knots will be
possible for VTN during a brief period around midday Sunday.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 10 PM CDT /9 PM MDT/ this evening for
NEZ004>010-022>029-035>038-056>059-069>071-094.
&&
$$
SHORT TERM...Meltzer
LONG TERM...Meltzer
AVIATION...NMJ
Area Forecast Discussion
National Weather Service Louisville KY
947 PM EDT Sat Apr 30 2022
.Mesoscale Update...
Issued at 948 PM EDT Sat Apr 30 2022
The first wave of convection has stayed subdued as expected early
this evening. However, we are starting to see a slow uptick in
coverage and intensity as the stronger low level jet core
overspreads the area, and the mid level cap starts to erode a bit.
This trend should continue through the next few hours, with
scattered to numerous thunderstorms expected overnight ahead of the
approaching front. Although we have lost a bit of surface based
instability, we still have modest to moderate MU CAPE values in the
1000-1500 J/KG range that should persist through the overnight. In
addition, a second ML CAPE axis just ahead of the front should
overspread the area again around and after Midnight. So, do think
that an isolated damaging wind and hail threat will still exist with
the strongest storms. Still think the overall tornado threat is low,
but not zero as the initially more favorable low level wind field
should veer with time and create an overall more unidirectional
shear profile.
Previous Update...
Issued at 537 PM EDT Sat Apr 30 2022
Things are quiet across our CWA at this hour, however convection is
beginning to fire off to our west along two distinct axes. The lead
line of broken convection is currently stretching from the
Ohio/Mississippi River confluence up through the lower Wabash River
Valley. Oddly enough, this convection is embedded in an area of
minimal instability, but appears to be driven/forced by the narrow
low level jet axis and/or some differential heating. A look at
satellite imagery also shows the convection embedded in/near a
corridor of heavy cloud cover, which makes sense that it is more
forced given the overall instability minimum between our unstable,
but capped environment, and the main instability axis farther to the
west just ahead of the main front. Overall, don`t expect this lead
convection to do much as it enters our CWA over the next few hours.
HRRR has picked up on this activity, but shows it mostly weakening
later this evening (at least initially).
Although there isn`t as much concern for the initial convection,
there is some concern for what could occur between 00-09z as a
stronger core of the low level jet ramps up (40-45 knots), and
enough instability (1000-2000 J/KG of MUCAPE) lingers through much
of the overnight. We will be holding onto 500-1000 J/KG or less of
SB CAPE by this time so a widespread severe threat should be
somewhat diminished, however overall coverage and intensity of
actual storms may increase through 03 or 06z given the added
forcing. So, think that an isolated wind/hail threat could still be
on the table overnight. The overall shear profile does look to
become more unidirectional with time, although can`t rule out a few
supercells (perhaps a few splitters?) in that 00-06z time frame
given a somewhat veered profile. The overall low level shear
component is lacking a bit for a more concerning tornado threat
later this evening, but it isn`t zero either. Will have to see how
things evolve, and if the low level winds stay backed or veer pretty
quickly to a more unidirectional overall profile.
Did also want to mention that we do have a moderate amount of
instability over our area right now, however we are capped just
above 700 mb. Outside of the convection entering our CWA from the
west, this should mostly keep our area in check until the cap erodes
between 00-03z. That timing also lines up with the arrival of the
LLJ/forcing which also makes sense. So, the bottom lines is that the
severe threat should begin increasing by 8-9 PM EDT.
&&
.Short Term...(This evening through Sunday)
Issued at 330 PM EDT Sat Apr 30 2022
...Possible Strong-to-Severe Storms Tonight...
Synopsis...An upper-level low and associated occluded surface
reflection will slowly transition from the High Plains to the Upper
Midwest. This will push a cold front towards the lower Ohio Valley
tonight, so expect storm chances to ramp up after sunset. Meanwhile,
central Kentucky and southern Indiana have been in the warm sector
this afternoon with a higher than previously thought warming and
destabilization given the early dissipation of the cloud debris.
Models are generally depicting the current state fairly well;
however, they start differing once the front moves through our area
with varying degrees of convective intensity as the storms move to
the east. Although the aforementioned scenario is certainly
plausible due to the lack of diurnal instability, the strongest
outputs represent a more continuous threat thanks to a sustained LLJ
intrusion.
Rest of Today - Tonight...The rest of this afternoon should stay
partly cloudy with a low chance of isolated showers to the north
while temperatures and dewpoints top around the low 80s and 60s,
respectively. Then, the cold front will be entering southern Indiana
by 1/00Z and progressively move through the rest of the forecast
area until right before sunrise tomorrow when most of the storms
will be moving east of I-75. As mentioned in previous forecast
packages, there is a possibility of strong-to-severe storms for
tonight, mainly along and behind the frontal line. The main severe
threat with the strongest cores is damaging wind, although hail is
not out of question if discrete organized convection is realized and
lasts long enough. The current reasoning for tornado risk is very
marginal given the rapid near-surface destabilization. Forecast
soundings favor a conditional chance of a brief spin-up in southern
Indiana in the early evening given the low-level kinematic and
thermodynamic parameters. Nonetheless, deep layer shear will lag
behind the warm sector and the frontal line, which undermines a
greater confidence on storm organization and updraft maintenance.
Finally, there is a marginal risk of localized flooding concerns
west of I-75 that overlaps with the better storm coverage and
healthier rain rates. However, it is important to note that the
lowest 1-,3-hr FFG is placed at this moment around the Cumberland
and an small section of the Bluegrass area. Taking into account the
moisture content and slow Corfidi upshear vectors, some instances of
flash flooding might occur in the previously-mentioned areas should
the frontal line maintains the strong convection.
Tomorrow...Improving conditions area-wide as the post-frontal rain
exits to the east after sunrise. Temperatures will stay a few
degrees above normal even though not as warm as today, for example.
Sunday afternoon will be rain-free, with mostly clear skies, and
gusty westerly winds.
.Long Term...(Sunday night through Saturday)
Issued at 205 PM EDT Sat Apr 30 2022
...Chance of strong/severe storms Tuesday...
Synopsis: Expect an active stretch of weather this coming work week
as several upper waves are progged to move through the area. Chances
of showers will be present through much of the week with the best
chances for thunderstorms Tuesday and Friday as cold fronts sweep
through the OH Valley.
Discussion: By Sunday night, clearing skies will prevail as the cold
front pushes east to the Appalachians. Pleasant conditions will
continue through Monday early afternoon as surface high pressure
skirts across the OH Valley under brief upper level ridging. Expect
morning lows in the upper 40s to low 50s Monday with afternoon
temperatures rising into the mid to upper 70s for most, while some
urban locations and areas along the KY/TN border peak around 80
under increasing mid to high cloud cover.
Tuesday will be our next active weather day as a closed 5H low over
the Central Plains and associated surface low advances NE into
IN/OH. Rain showers with embedded thunderstorms will spread across
the area as a surface warm front lifts northward through the
Commonwealth accompanied by a 45-50kt LLJ and a moist atmosphere
thanks to deep SW flow. There is potential for strong to severe
storms Tuesday as models advertise ample instability with CAPE
values around 1500 J/kg alongside modest shear and surface dew
points in the mid 60s. Model disparity exists as to exactly when and
where the cold front will reside by Tuesday evening, but will
closely watch this system as new data becomes available.
Wednesday will likely see residual light precip in the form of
either light rain or light drizzle for some as the system exits to
the NE, but dry conditions should prevail for the latter portion of
Wednesday through Thursday late morning as brief low amplitude
ridging moves through the area. A cooler air mass and cloud cover
will also serve to quell temperatures a bit with afternoon highs
only reaching into the upper 60s to low 70s.
Forecast confidence decreases beyond Wednesday as models greatly
diverge in their handling of another closed upper low that will
traverse the Rockies and head toward the OH Valley. GFS and CMC show
the system moving rather progressively and pushing to our NE by late
Friday night. This would likely lead to a dry Saturday (though GFS
soundings do show lingering low level moisture indicative of a
drizzle scenario through the early morning hours). The Euro on the
other hand has a much slower solution with the surface low lingering
over the OH Valley throughout the weekend. Will go with a model
blend for now with mention of chance showers for Saturday, but this
will likely change over the coming days.
&&
.Aviation...(00Z TAF Issuance)
Issued at 749 PM EDT Sat Apr 30 2022
Numerous showers with a few embedded rumbles of thunder have arrived
near the HNB TAF site at this hour. Expect coverage and intensity to
increase at the rest of the TAF sites between 10 PM and 2 AM EDT
tonight as a stronger low level jet overspreads the area and the
main frontal boundary arrives. Will mention prevailing SHRA with
some VCTS and TEMPO TSRA to cover that threat.
Also expect a brief window for VFR/MVFR threshold ceilings as the
front passes in the pre-dawn hours. This will be accompanied by a
shift in surface winds from SSW to SW or even WSW. Any MVFR period
will be brief overnight. Expect skies to quickly clear out and
prevail VFR for the daylight hours of Sunday. Gusty SW winds between
20 and 25 mph will be possible at times.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Mesoscale...BJS
Short Term...ALL
Long Term...CG
Aviation...BJS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
637 PM CDT Sat Apr 30 2022
.MESOSCALE DISCUSSION...
Issued at 628 PM CDT Sat Apr 30 2022
While our tornado threat continues to decrease across the area
following the northward passage of the warm frontal boundary, the
threat for severe weather will continue in the watch area for
for the next couple hours (especially east of the I-39
corridor). Skies have cleared south of the warm front and ahead
of the approaching cold front and this has allowed surface
temperatures to warm back into the lower 70s amidst lower 60s
dewpoints. The net result being increasing MLCAPE values just
ahead of the cold front to around 1,000 J/KG per SPC RAP
Mesoanalysis. Continued lower level confluence associated with
the approaching cold front will thus continue to maintain the line
of northeastward moving convection for at least next hour or two
as it moves into eastern IL. The KLOT VAD wind profile along with
recent radar imagery suggests that quasi linear storm clusters
will be the primary mode of convection as it approaches eastern
IL. The main severe threat with this activity for the next couple
hours will be damaging wind gusts and hail.
It appears the storms may begin to diurnal weaken as the approach
the IN state line in the next couple hours. For this reason, the
SPC is not currently planning a new watch downstream into IN, but
this will continue to be monitored.
KJB
&&
.SHORT TERM...
Issued at 308 PM CDT Sat Apr 30 2022
Through Sunday night...
A tornado watch was recently issued for much of my northern IL
counties, with the exception of Lake and Cook in far northeastern
IL. The watch will run through 8 pm this evening.
Increasingly diffluent upper level flow associated with the exit
region of a mid/upper level jet max continues to overspread the
northward shifting warm sector early this afternoon. This is
noted by the recent uptick in thunderstorm development across
western parts of the area. Severe concerns with these storms over
the next few hours will be hail and possible tornadoes,
especially with any storms that are able to root themselves near
the surface warm front, where increasingly backed surface flow
(hence higher effective helicity) resides. However, the main
negating factor to the overall tornado threat continues to be the
extensive stratus deck that has overspread much of northern IL,
and is limiting further destabilization. This may limit the
overall tornado threat, especially with northeastward extent into
the Chicago metro area. Nevertheless, we will need to continue
monitoring the storms as the strongest ones will be capable of
producing some hail. Damaging winds will also become possible with
the stronger storms amalgamate into clusters as they migrate
eastward late this afternoon. Expect the storms to end from west
east early this evening.
Sunday will be a cooler and breezy day as the occluded surface low
gradually fills as it shifts into the upper Great Lakes. Expect
highs mainly in the 50s.
KJB
&&
.LONG TERM...
Issued at 159 PM CDT Sat Apr 30 2022
Monday through Saturday...
Following what will be a rather quiet Sunday, there will be no
shortage of rain chances next week with a couple of more storm
systems on the horizon. Monday will begin on a tame note with just
some mostly cloudy skies and morning lows in the 40`s. Temperatures
will climb into the upper 50`s and 60`s by the mid-afternoon with
the help of some height rises aloft. Meanwhile, a negatively tilted
trough will move through the Plains and into the Midwest through the
day on Monday. As the trough propagates into the Midwest late
Monday, it`s forecast to lose out on a good amount of it`s amplitude
resulting in the associated surface Low steadily weakening as it too
inches into the Midwest Monday night. However, the near-storm
environment remains as such that a few thunderstorms still appear
likely, some of which could be on the stronger side. The rain will
arrive Monday evening as shower pop up along the system`s warm front
and will continue through most of Tuesday. The greatest chance for
seeing a few thunderstorms will occur Tuesday afternoon and evening
as the Low pressure center passes through the CWA. The greatest
potential for a couple of stronger thunderstorms appears to exist
south of I-80, but this could very easily change as any little shift
in the storm`s track. Additionally, if the storm`s center were to
pass through the CWA as guidance currently suggests, highs on
Tuesday will range from the lower 50`s in the northern CWA to the
upper 60`s further south.
Wednesday will feature a pretty good deal of sunshine, something we
will not be seeing much of next week. We`ll be getting some
sufficient, but brief, dry air advection aloft with higher pressure
setting in from the northwest. Despite the sunshine and drier air,
cool northerly winds will have us finding ourselves in the upper
50`s and lower 60`s once again on Wednesday afternoon. Cloud cover
will build through the latter part of Wednesday as more moisture is
advected in on the lee side of an enclosing trough. This trough will
provide us with our second storm system of the week come Thursday.
The forecast for the this system has changed quite a bit since this
time yesterday. Whereas the upper level trough was originally slated
to be progress through the lower Midwest dragging the surface Low
well to our south through the lower Missouri and Ohio Valleys, now
guidance has the trough moving through the heart of the Midwest
bringing the surface low pressure center much closer to the CWA. An
incredibly saturated profile will result in widespread rainfall on
the northern flank of the storm. However, no instability means the
rain will be purely stratiform in nature and shouldn`t amount to
anything more than light to moderate showers. The rain will arrive
as early as early Thursday morning and last through roughly the
first half of Friday. Highs for the latter half of the week will
remain fairly steady with upper 50`s and lower 60`s in the forecast.
This includes on Saturday when we will finally see some more
sunshine and primarily dry conditions to kick off the weekend.
Doom
&&
.AVIATION...
For the 00Z TAFs...
A second line of thunderstorms is en route to the terminals, with
the exception of RFD whose thunderstorm chances have just about
dissipated for the night. These storms are expected to reach the
Chicago terminals shortly after 00Z and be short-lived likely
remaining in the vicinity for only an hour or so. Heavy rain, strong
wind gusts, and small hail appear likely underneath these storms.
Such conditions could easily pull visbys down into MVFR or even IFR
territory for brief periods. The thunderstorm threat should conclude
with the passing of this next line, perhaps with the exception of a
stray light thunderstorm or shower trailing behind.
Winds throughout this event have been troublesome teetering back and
forth between SW and SE. Wind are expected to establish a SSE
direction immediately ahead of the line of storms and veer west of
south behind the line. From this point on, winds should hold steady
at a SSW to SW direction for the remainder of the TAF period. Gusts
of 15-20 kts will persist through the remainder of the evening and
through the night. Near daybreak Sunday morning, cigs are expected
to drop below MVFR thresholds and the SW winds will increase
slightly as the morning progresses. Conditions are then expected to
be rather consistent with breezy SW winds and MVFR cigs through the
remainder of the TAF period.
Doom
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...Wilmette Harbor to Michigan City IN until
9 PM Saturday.
Small Craft Advisory...Winthrop Harbor to Wilmette Harbor until
1 AM Sunday.
&&
$$
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Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1037 PM CDT Sat Apr 30 2022
.SHORT TERM... (Through Late Sunday Afternoon)
Issued at 238 PM CDT Sat Apr 30 2022
The primary concern for the short term is obviously the ongoing
threat for severe thunderstorms ahead of the cold front late this
afternoon/early evening. All CAMS show convection across east
central and southeast Missouri into southwest Illinois to a greater
or lesser degree this afternoon and evening. The HRRR and HiRes-FV3
are perhaps the most robust, showing several discrete cells this
afternoon, growing upscale into a line. SPC mesoanalysis is already
showing 2000+ J/Kg SBCAPE that`s uncapped or virtually so. This
might be a bit overbaked the RAP dew points are a little high
compared to surface obs. That being said, the MLCAPE is 1000-1500
J/Kg and is forecast to increase over the next 2-3 hours, most
likely due to dew point pooling ahead of the front, and some
slightly steeper low level lapse rates developing due to daytime
heating. 0-6km bulk shear is 40-50kts, with 0-1km shear of 20-
25kts, and some low level curvature to the hodographs, so rotating
storms look likely, and all severe weather types will be possible
including damaging winds, large hail, and a few tornadoes.
Consequently, a tornado watch was issued a short time ago for
southeast Missouri and southern Illinois until 01Z.
After the front moves through this evening, we should see a drier
airmass move into the Mid Mississippi Valley for Sunday. It looks
breezy again tomorrow behind the front, particularly across
northern Missouri and central Illinois where the pressure gradient
will be tightest. West winds of 15-20mph with gusts in excess of
30mph look likely up there with somewhat weaker winds further
south. The west wind won`t promote strong cold advection, so highs
on Sunday will be similar to today`s across most of the area, but
northern Missouri into central Illinois will see cooler temperatures
than today as they will be closer to the cold core of the low over
the Upper Midwest.
Carney
.LONG TERM... (Sunday Night through Next Saturday)
Issued at 238 PM CDT Sat Apr 30 2022
Monday through Saturday next week should continue the active weather
pattern with a train of short waves moving from the Pacific across
the CONUS. The first wave is actually moving across the Pacific
Northwest at this time and it will be dug in over Colorado by Monday
morning. The resulting lee-side cyclogenesis will turn the low
level flow back to the south over the Mississippi Valley which will
bring rich low level moisture back into Missouri and southern
Illinois. Deterministic guidance shows moderate to strong low level
moisture convergence Monday into tuesday as the wave moves east-
northeast across the Midwest resulting another round of wet weather
for that time period. Deterministic guidance is showing 1000+ J/Kg
of MUCAPE hanging across southern Missouri and Illinois Monday night
into early Tuesday morning with 30-40kts of 0-3km and 0-6km shear
respectively. SPC is hinting that we could see some nocturnal
severe weather due to these conditions, and this looks reasonable at
the moment. CAPE increases pretty rapidly on Tuesday ahead of the
front thats associated with our short wave, so the severe weather
threat may continue for parts of southeast MO/southern IL into
Tuesday until the front pushes through.
Current indications are that we`ll have a respite in the wet weather
on Wednesday behind the front, but the next short wave digs into the
western Plains on Thursday to set up a very similar pattern for late-
week as we will see Monday and Tuesday. According to the
deterministic models, Thursday-Friday will be wet and stormy again,
with a potentially dry day on Saturday. WPC cluster analysis is
showing some variance with the timing and amplitude with both the
late-week short wave as well as the upstream ridge following in its
wake. This obviously lends some uncertainty to the timing of the
rain and the strength of any potential convection. Temperatures
through the period continue to look mild to a bit cool with highs
strong low level mi mainly in the mid 60s to low 70s and lows in the
mid 40s to mid 50s.
Carney
&&
.AVIATION... (For the 06z TAFs through 06z Sunday Night)
Issued at 1035 PM CDT Sat Apr 30 2022
Cold front and precipitation has moved well east of the TAF sites.
So dry VFR flight conditions for TAFs along I-70 corridor.
However, ceilings will lower across portions of northeast Missouri
and west central Illinois due to wrap around clouds on back side
of system. MVFR flight conditions expected at KUIN between 12z and
20z Sunday. Otherwise, gusty west winds which will diminish by
Sunday evening.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Spokane WA
353 PM PDT Sat Apr 30 2022
.SYNOPSIS...
Some showers will linger into Saturday evening. Otherwise drier,
warmer weather is expected on Sunday as a weather system pulls
away from the area. More rain is possible on Monday. Some
locations may reach 70 degrees for the first time this spring
Wednesday or Thursday, before the next system moves in.
&&
.DISCUSSION...
Tonight and Sunday: Band of stratiform rain over northern
Washington into the North Idaho Panhandle will continue to stretch
and weaken into early this evening as a closed low over NW Oregon
drops south and away from the area. Meanwhile a cluster of showers
and thunderstorms over NE Oregon developed this afternoon in
response to sun breaks destabilizing the atmosphere. Lightning has
been on the decrease but the area of moderate to heavy rain
continues and will be pushing in towards the Blue Mountains and
Camas Prairie this evening as well as the Lewiston area. Rain
cooled outflow wind gusts of 25-35 MPH are possible between 4-6 PM
this evening in these areas. Isolated thunderstorms are possible
as well. Some of this activity may impact the palouse as well but
with the low dropping south and away from the area into the
evening confidence is lower. This activity will diminish overnight
into Sunday morning as the low drops all the way into central
Nevada by 18z Sunday. Lingering boundary layer moisture over the
northern valleys and Spokane/Coeur d`Alene area and some breaks in
the clouds overnight may allow for patchy fog development by
Sunday morning. A short wave ridge moves over the region on Sunday
for warmer and drier weather. High temperatures will rise back up
towards seasonal normals in the upper 50s to mid 60s. JW
Sunday night through Saturday: The potential for precipitation
continues into early next week, followed by a drier and warmer
pattern before the next trough and precipitation chances arrive
Thursday onward. The pattern will also favor some breezy
conditions and temperatures pushing above normal, especially
around mid-week.
First between Sunday night and Monday the next low (currently
coming into the Gulf of AK) makes it ways into the region, with
the model tracking its center just to the south of our CWA before
it moves toward the Great Basin and ridging starts in for Tuesday
and Wednesday. The low will start to bring precipitation chances
toward the Cascades late Sunday night, then across the rest of our
region Monday. However the track of the low will keep the the
highest PoPs over over the Cascades and central to southeast WA
and lower ID. Some model indicate the risk for heavier
precipitation amounts over southeast WA/lower ID into Monday
afternoon/Monday night. The NAM holds the precipitation back
longest. Overall ensembles suggest about a 60 to 90% chance of
wetting rains (>=0.10" of precip) over the west and southern CWA
through 12Z Tuesday. But the amounts the NAM suggests are no
favored by the ensembles which keep the potential for >0.50" of
rain just to the southeast of our region. Additionally the passing
trough carries some instability, which leads to the potential for
about 10-15% chance for t-storms over the north and eastern CWA
for Monday afternoon/early evening.
For Tuesday and Wednesday the area, for the most part, dries out
as a ridge builds in. An impulse riding down the backside of the
exiting long-wave trough will keep some limited shower chances
alive over the eastern mountains Tuesday, but otherwise look for a
mix of sun and clouds. Then from Thursday to Saturday the ridge
axis starts to shift east and a trough approaches the coast.
Models do not agree on how quickly it moves inland, with the ECMWF
slower and drier than the GFS. However either way the door is
opened for impulsing riding in ahead of the trough in the
southwest, with a milder and more unstable and moist atmosphere.
Thus PoPs increase across the region. Overall there are about
15-20% PoPs over the Basin/Valley areas and the mountains zone
have about a 30 to 50% chance at this point. This also includes
about a 10-15% chance of t-storms over northern WA/north ID for
Thursday afternoon. Chances will also have to be monitored for
Saturday.
Temperatures warm to near normal early next week, then push above
normal into the middle of the week before cooling again some
toward next Friday and Saturday. Wednesday and Thursday continue
to look like the warmest days, with highs in the upper 60s to mid-
70s outside of the mountains. /Cote`
&&
.AVIATION...
00Z TAFs: Expect deteoriating conditions at KPUW/KLWS this evening
as band of moderate to heavy showers approaches. A few
thunderstorms may develop around the Blue Mountains as well with
low confidence of any of the terminals receiving a thunderstorm. Latest
guidance suggests these will impact KLWS beginning with westerly
outflow winds followed by moderate to heavy rain showers. KPUW may
be on the fringes of this activity but current radar trends and
latest HRRR model suggests some showers over the area this
evening. Meanwhile a combination of precipitation and winds
shifting to an upslope west-northwest direction will lead to
lowering CIGS. HREF guidance shows a 70% chance of CIGS lowering
to IFR overnight. Elsewhere rain is coming to an end with
afternoon CIGS rising to between 2000-5000 feet. Fog and stratus
are likely for the northern valleys around Winthrop, Omak, and
Colville Sunday morning as some clearing combined with a moist
boundary layer allows for fog/stratus development. Some fog
patches are also possible around Spokane and Coeur d`Alene but
with less of confidence of clearing VFR conditions are forecast.
JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 37 61 41 61 40 64 / 20 0 0 40 20 0
Coeur d`Alene 38 60 40 63 42 61 / 30 0 0 30 30 10
Pullman 39 56 41 56 39 57 / 50 10 0 60 50 10
Lewiston 44 63 44 60 44 64 / 60 10 0 70 50 10
Colville 36 65 41 65 40 71 / 20 0 0 30 20 10
Sandpoint 38 61 40 62 42 61 / 30 10 0 30 20 10
Kellogg 37 58 41 62 42 56 / 40 10 10 40 40 10
Moses Lake 37 67 45 60 39 70 / 20 0 0 60 20 0
Wenatchee 39 68 47 56 42 67 / 20 0 10 60 20 0
Omak 37 68 46 64 43 73 / 20 0 10 60 20 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Paducah KY
1010 PM CDT Sat Apr 30 2022
.UPDATE...
Issued at 1010 PM CDT Sat Apr 30 2022
During the last 30 minutes, the western two thunderstorm clusters
were beginning to become more outflow dominated. Although more
unidirectional, KPAH VAD wind profile still showing an impressive
50kt southwesterly flow in the 2-7kft layer. There is still some
potential for sub-severe winds during the next hour or two.
Overall, the severe potential has decreased enough to let the
Tornado Watch #164 expire at 10 pm CDT.
Will be monitoring for some low-end wind gusts and potential for
isolated flooding potential with thunderstorm clusters through
midnight.
UPDATE Issued at 752 PM CDT Sat Apr 30 2022
Per coordination with the Storm Prediction Center and NWS St.
Louis, keeping current Tornado Watch Number 164 in place from 8 pm
through 10 pm, covering the same area. Minor wave and low level
convergence over southeast Missouri still supporting some increase
veering through 12kft, with persistent 35-45 knot winds just off
the surface near 1kft off the surface per the KPAH VAD wind
profile. Decent dry line west of the current convection should be
the tail end of the activity in the watch area during the next two
hours.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 130 PM CDT Sat Apr 30 2022
The RAP did a good job depicting the corridor of drier air over our
CWFA centered between two low trop moist axis to our east and west.
Surface dew points have dropped into the 50s most of the area, with
a lot of debris cloudiness over the west 1/2 of the CWFA.
SPC just issued a mesoscale discussion for our area. But overall our
thinking has not changed. While there is certainly a risk for a few
severe storms, we are not expecting a big event. Better forcing for
ascent with jet dynamics stay more to our north. Not much speed
shear with flow at and above 700mb staying in the 40-45 kt range up
to near the EL. The one area we continue think might have the best
chance of isolated severe is SEMO, into briefly far west KY and the
southern tip of Illinois. This is supported by higher probabilities
seen across this area in the SSCRAM (RAP/HRRR), with the most likely
hazards marginally severe hail and high wind. After 00z, the low
level flow actually weakens with 40kts of S/SW flow dropping down to
25 kts or so. MLCAPES that peak 1500 j/kg or slightly higher in the
aforementioned areas quickly diminishes south as well. So the window
of opportunity does not seem all that long into the evening. For
storm mode, mainly clusters, or short line segments. There could
be a brief supercell storm or two, again in the favored areas
mentioned.
As the parent system to our north heads into Canada, and after the
weak front moves across the area, our chance for convection will end
from west to east tonight, with dry weather expected Sunday and
Sunday night. It will be breezy and warm Sunday.
.LONG TERM...(Monday through Saturday)
Issued at 244 PM CDT Sat Apr 30 2022
The first of many 500 mb shortwaves will set the stage for a fairly
active week as the chance for pcpn will be on the increase during
the afternoon Monday, especially across southeast MO. The period
with Categorical PoP does not begin until Monday night as showers
and tstms will increase in coverage across the FA. Elevated CAPE
will be the greatest across southeast MO and the Purchase Region of
west KY where SPC currently has a marginal risk for severe weather.
The main hazard will be the potential for some hail. Risk for
showers and tstms then continues through Tuesday as a sfc low
pressure moves across the Ohio Valley with a trailing cold front. A
few strong to severe storms with strong winds and frequent lightning
are possible as GFS BUFKIT soundings show CAPE values around 1500-
2000 J/KG and steep mid level lapse rates. High temps during this
period will range from the mid to upper 70s for most locations.
The risk for showers and storms may linger into Wednesday morning if
the front remains close enough to the FA, especially near the TN
border. However, the more likely scenario is for the front to stall
far enough south allowing for dry air to build in as a sfc high
pressure passes by to the north. Pncpn chances will gradually lower
from north to south. Temps will also be a bit cooler with highs only
near 70 degrees.
Lower confidence once again begins Thursday as models differ in the
timing of a sfc low pressure system that looks to move through the
lower Ohio Valley. The 12z ECMWF/CMC are in better agreement
compared to the 12z GFS which remains the big outlier with pcpn
arriving early Thursday morning. While PoP chances are more likely
across western counties in the afternoon, would favor the Thursday
night into Friday time frame for when pcpn will be the most
widespread across the area. At the moment, it appears the greatest
instability will remain to our south with more organized storms;
however, it will not take much of a shift north with the sfc low to
bring the better parameters for storms into the PAH CWA. Too early
to go into details for Saturday as it is unclear how quickly pcpn
chances will diminish. High temps will range from the upper 60s to
mid 70s during the period.
&&
.AVIATION...
Issued at 620 PM CDT Sat Apr 30 2022
For the 00z Sunday WFO PAH TAF issuance, kept VFR ceilings and
visibilities in advance of the primary storm line. With the
supercell over Wayne county MO, leaned to MVFR ceilings and
visibilities for the KCGI TAF with the potential for some small
hail near the airport within the first 1-2 hours of the forecast
period. If the cell weakens significantly before 02z Sunday, will
likely drop any mention from the TAF.
Otherwise, tried to keep any VFR/MVFR visibilities limited to a
1-3 hour time period with the main convective activity, persisting
it a little longer for the KEVV and KOWB TAF sites through at
least 05z.
Beyond that time, VFR conditions will dominate the rest
of the forecast period for all TAF sites.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...Smith
SHORT TERM...CN
LONG TERM...DW/SP
AVIATION...Smith
Area Forecast Discussion
National Weather Service Phoenix AZ
513 PM MST Sat Apr 30 2022
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
A progressive weather pattern will remain in place through next
week with weather disturbances passing north of the region. This
pattern will keep temperatures in the mid 90s each day, with
mostly sunny skies. Breeziness is expected each afternoon while
windy conditions are likely Sunday and Tuesday, with each passing
disturbance. Seasonably dry conditions will continue and no rain
is expected through the next seven days.
&&
.DISCUSSION...
Latest RAP streamline analysis reveals a short-wave ridge across
the intermountain West and a closed low across the Pacific
Northwest. Across the Desert Southwest, the ridge has helped to
boost temperatures several degrees today with lower desert highs
in the mid 90s. Meanwhile, dewpoints are considerably lower than
they were this time yesterday, generally in the teens and 20s.
The aforementioned low pressure system will dive southeastward
into southern UT by early tomorrow evening. PWATs of 0.2-0.3
inches remain insufficient for precipitation, instead main impact
across our area will be an increase in wind Sunday afternoon.
ECMWF EFI anomalies are generally less than 0.5, nevertheless the
ECMWF ensemble indicates gusts of at least 30 mph will be likely
in the Valley ahead of the trough axis. Stronger gusts will be
possible across the higher terrain north and east of Phoenix,
resulting in a high fire danger.
&&
.PREVIOUS DISCUSSION...
Brief shortwave ridging returns on Monday before yet another
shortwave passes by to the north on Tuesday. This system will
likely lead to another period of breezy to windy conditions, but
at this time most guidance shows speeds a bit lower than Sunday.
WPC cluster analysis shows good agreement on the pattern
progression heading into the middle to end of next week, with
about 75% of guidance suggesting somewhat stronger ridging will
set in. The other 25% still show a warm and dry pattern, but
perhaps a bit cooler and windier with a weak trough along the west
coast. NBM temperature guidance reveals very little uncertainty
for the next 5 days with high temperatures in the middle 90s. It
does suggest that high temperatures may climb a bit under the
stronger ridging, but with more uncertainty as well. The NBM
temperature probabilities of reaching 100 F in Phoenix never climb
above about 10% in the next week, so our first such reading will
likely wait a little longer than typical.
&&
.AVIATION...Updated at 00Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds will be light to moderate, aob 10 kts with a few gusts into
the teens through the early evening and follow typical diurnal
patterns. With an ozone air quality alert through this evening,
there may be some increased haziness that could impact slantwise
visibility early in the period. By mid-late Sun morning S
component crosswinds near 8-11 kts are expected. By late Sun
morning to early afternoon windspeeds will increase with the SW-
WSW switch with gusts of 20-25kt through Sun afternoon and early
evening. Mostly clear skies with FEW high clouds to become clear
by later this evening or tonight.
Southeast California/Southwest Arizona including KIPL and KBLH:
Light winds will increase somewhat this evening by around 02Z at
KIPL with gusts of 20-25 kts followed by S wind by mid morning
Sun. Then gusty W winds resume again by early Sun afternoon with
gusts upwards of 25 kft. Lighter winds at KBLH will favor normal
diurnal patterns through midday Sun. Then gusty SW winds develop
by early afternoon with gusts near 25 kts. Mostly clear skies with
FEW high clouds to become clear by later this evening or tonight.
&&
.FIRE WEATHER...
A progressive weather pattern will remain in place with a series
of troughs passing north of the region. This will keep conditions
dry with very little cloud cover and no chance of rain in the
next week. As is typical for this time of year, breezy conditions
will develop each afternoon, but the breeziest days are expected
to be on Sunday and again Tuesday, with the passing of the next
couple of troughs. Wind gusts these days could reasonably reach
25-35 mph, especially over the higher terrain north and east of
Phoenix. With above normal temperatures in the 90s (low
elevations) and Min RHs between 5-15% each afternoon, elevated
fire weather conditions will remain a concern through the
forecast.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Red Flag Warning from noon to 10 PM MST Sunday for AZZ133.
CA...None.
&&
$$
Visit us on Facebook, Twitter, and at weather.gov/phoenix
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Hodges
AVIATION...Sawtelle/Heil
FIRE WEATHER...Hodges/Benedict
Area Forecast Discussion
National Weather Service Shreveport LA
908 PM CDT Sat Apr 30 2022
.UPDATE...
Frontal boundary along a line from near Prescott to Shreveport to
Nacodoches gradually moving east. Despite MLCAPE values of 3500
J/kg and steep mid-level lapse rates, convection has dissipated
across most of the region with the exception of portions of south-
central Arkansas. Latest HRRR model suggests convection to
reignite within the next few hours along the front as it shifts
south of I-20. Therefore, only made minor adjustments to the watch
at this time, removing counties that are now on the drier side of
the boundary and leaving the remainder of the watch intact. /05/
&&
.PREV DISCUSSION... /issued 635 PM CDT Sat Apr 30 2022/
AVIATION...
For the 01/00z TAFs, convection continues along a cold front from
near ELD to SHV to near TYR, progressing eastward. The front is
forecast to stall across east Texas and north Louisiana overnight
before lifting northward on Sunday. VCTS conditions expected
across SHV/MLU/ELD/LFK terminal sites through the evening with
VCTS conditions continuing across LFK through late morning
Sunday. Otherwise, could see tempo MVFR ceilings across mainly
MLU/LFK around daybreak, improving to VFR by 01/18Z. /05/
/05/
PREV DISCUSSION... /issued 330 PM CDT Sat Apr 30 2022/
SHORT TERM.../Tonight through Sunday Night/
At 20z, a cold front was located from near Hot Springs, to
Ashdown, to Pittsburg, to Athens. Scattered convection has
repeatedly tried to develop along the front in Southwest Arkansas
but has struggled. Latest radar loops are indicating signs of
development farther southwest into Central and East Texas, which
suggests convective initiation is underway. Latest mesoanalysis
suggests the atmosphere is strongly unstable, with CAPE values in
excess of 3000 J/kg. However, there is little in the way of large
scale forcing at present. That should change over the next
several hours as a weak axis extending southward from a deep
upper trough over Nebraska and Iowa moves across the area this
evening and tonight. Convective coverage should continue to
increase along the front. Despite deep layer shear of only 20 to
30 kts, the strong instability and steep lapse rates should be
more than sufficient to support a risk for severe weather posing a
risk for large hail and damaging winds. Low-level SRH values are
rather modest, but an isolated tornado cannot be ruled out.
The convection and the front will continue southward across the
area tonight, and the threat for severe weather should end with
the frontal passage. After midnight, the risk for any additional
severe weather should be limited to Deep East Texas and Central
Louisiana where the front is expected to stall. However, what
little large scale ascent we have should be diminishing, so the
convection should also gradually weaking and decrease in coverage,
especially during the early morning hours. However, rain chances
will persist along the frontal boundary.
The front will rapidly return northward Sunday morning, and a few
isolated showers or thunderstorms will be possible across our
southernmost zones where moisture availability remains high.
Little to no effect on our temperatures will occur, as daytime
highs will still climb into the mid 80s areawide on Sunday.
Chances for more showers and thunderstorms return Sunday night and
into Monday morning as a convective complex develops ahead of the
dryline over West Texas and moves east-northeast across the
Southern Plains and towards the ArkLaTex.
CN
LONG TERM.../Monday through Saturday/
Well the weekend cold front is lifting back northward early, but
will quickly get another push into our area mid to late day Monday.
A short wave over the plains states with the GFS is an open wave of
561dam and the ECMWF is closed low at 560dam. Typically a much
slower trend going forward in time and not as progressive open waves
with all the rings of isoheights aloft.
The ECMWF is the more optimistic for rain for us during this
timeframe while the GFS struggles with not much signal anywhere in
the midSouth. A deeper upper low will be on approach from midweek.
The long range models are in good agreement on position of a core
low in the deepening pattern over the Rockies. Once again this
feature will activate the lift aloft for the SPC day 6 to highlight
for us a Slight risk potentially.
By Friday 00Z on Thursday evening we have some timing differences on
players, but not so much on QPF signal. This may be the most we see
all week with a stronger frontal approach and then a bubble high of
1015mb over MO. Conversely the ECMWF is preceding much slower with
the upper on GFS in the western Atlantic, while the ECMWF has the
upper low still over KY/TN. Little difference for us in the four
state area as we are on the drier side of either solution.
Next Saturday looks good for us in either case with a 1019mb air
mass over the corn belt and the ECMWF 1017mb over NB/KN. So the
bottom line is little change for our work week with more of chance
for rainfall than not until that sfc front eases in for late work
week. Expect unseasonably warm temps to continue with mid to upper
80s for highs and about 20 degrees cooler by comparison for lows.
Even behind this front next weekend, the air will just be cooling
down briefly like it has been all Spring. We are seeing average
temps warm quickly during May with the longer days. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 64 86 67 85 / 50 10 10 30
MLU 64 85 66 85 / 60 20 10 20
DEQ 52 84 62 80 / 0 0 40 70
TXK 58 84 67 82 / 0 0 30 60
ELD 59 85 63 84 / 50 0 10 40
TYR 61 85 68 84 / 10 20 20 40
GGG 61 85 67 85 / 20 20 10 40
LFK 66 85 67 87 / 40 30 10 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
05/09/20