Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/30/24
Northern Alaska Forecast Discussion...CORRECTED
National Weather Service Fairbanks AK
1123 AM AKDT Sat Jun 29 2024
.SYNOPSIS...
Warm weather will continue over much of the Interior through the
weekend and into early next week. Areas of dense smoke from fires
burning is reducing visibilities over the Middle Tanana Valley.
Smoke will be in and out through the weekend. Dense smoke
advisories expected to continue. Isolated storms will persist
into the weekend.
&&
.DISCUSSION...
Analysis and Model Discussion...
A strong vertically stacked low will remain in the central Bering
Sea then drift across the Aleutians on Sunday as a 540 dam
Low. Ridging will persist over the Interior this weekend.
A trough will push across the eastern North slope late Sunday
into Monday. Another low over Russia will push a front across
Northwest Alaska on Tuesday. Ridging over the Interior will
slowly break down Monday and Tuesday. Models in good agreement
through the short term. The HRRR smoke model showing smoke
persisting over the Interior through the weekend.
Interior...Warm weather will continue over much of the Interior
through the weekend. Highs in the mid 80s and a few upper 80s over
the Yukon Flats. Areas of dense smoke from fires burning is
reducing visibilities over the Middle Tanana Valley. Smoke will be
in and out through the weekend. Air across Fairbanks and North
Pole is very unhealthy this morning. Dense smoke advisories have
been extended into Sunday. Smoke may thin and visibility may
improve in the afternoon around Fairbanks but become dense again
early morning on Sunday. High pressure builds back in for the
weekend with rising temps back into the 80s, and much lower
thunderstorm activity, with that ridge aloft suppressing
thunderstorm potential. Isolated to widely scattered thunderstorms
return over the southern Interior on Sunday.
West Coast and Western Interior...
High pressure in control over the majority of the west coast.
Western Interior will remain warm over the weekend with highs in
the upper 70s to low 80s. Showers continue to rotate around the
Yukon Delta from the low in the southern Bering through the
weekend. Widely scattered thunderstorms are possible from Grayling
to Mcgrath on Sunday. Some of these storms will be fairly strong
and may produce small hail and gusty winds with copious lightning.
Monday is another warm day, with increasing southwesterly winds
as a low approaches the NW Arctic. Possible change in the pattern
by Tuesday with temps cooling and a front bringing rain showers to
the west coast. Temps could drop to the 60s Tuesday into
Wednesday.
North Slope and Brooks Range...
A little less thunderstorm activity today but still a chance for
isolated thunderstorms over the eastern Brooks Range today from Anatuvak
Pass to the AlCan border. On Sunday, isolated storms return over
the southern Interior. A front will begin to impact northwest
Alaska and the western Brooks Range with strong west-southwesterly
winds.
Extended Forecast Days 4-7...
Long range models are coming more inline with a fairly large
pattern shift beginning Tuesday, as a front from E Siberia moves
inland across the NW Arctic and shifts east along the Brooks
Range and eventually into the Interior through the remainder of
the week. This will bring increasing west-southwest winds across
the Mainland each day, with increasing chances for rainfall and
cooler temps.
Coastal Hazard Potential Days 3 and 4...None.
&&
.FIRE WEATHER...
Warm and relatively dry over the Interior through the weekend and
into early Next week. Smoke and unhealthy air continues over
the Middle Tanana Valley down to Delta Junction. Dense Smoke
Advisories still in effect through Sunday. On Saturday, the
thunderstorm threat moves Anatuvak Pass to the AlCan border. For
now, widely scattered wet thunderstorms are expected. On Sunday,
isolated to widely scattered thunderstorms return over the
southern Interior and western Interior from Grayling to McGrath.
Major pattern shift begins Tue and Wed as the upper ridge breaks
down and a strong front moves into the NW Arctic and shifts east
through the week, bringing potential wetting rains and much cooler
temps, although strong southwest winds may create some critical
fire weather conditions prior to that. Will continue to monitor.
&&
.HYDROLOGY...
Heavy rain showers and thunderstorms over the Brooks Range today
may feed into faster moving streams and cause rapid rises, which
will remain high into this weekend. Glacial fed rivers including
the Tanana are beginning to rise as warming temperatures lead to
increased high elevation snowmelt.
&&
.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Dense Smoke Advisory for AKZ834-837-840-841-842-843-844-839.
PK...None.
&&
$$
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1038 PM EDT Sat Jun 29 2024
.SYNOPSIS...
A moist southwest flow will bring periods of rain with a chance
for thunderstorms into tonight. A cold front will bring
additional scattered showers and thunderstorms Sunday, some of
which could be strong to severe, mainly south and east of
Albany. Fair weather with cool and breezy conditions return for
Monday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
.UPDATE...As of 1035 PM...According to the ALY 00z sounding, we
officially broke today`s maximum daily PWAT value of 1.98" with
a new value of 2.06"! Needless to say, we remain highly
saturated throughout the area this evening. Despite this, showers
continue to decrease in coverage with the main coverage in the
Southwest Adirondacks. Higher reflectivity noted on the KENX
radar indicates some heavier downpours embedded within these
showers, but with rapid flow keeping them from remaining in one
place for too long, accumulations have not been too impressive.
In fact, the Old Forge Mesonet site only has about 0.34" for the
latest 1-hour accumulation.
Few updates were necessary with this update outside of minor
updates to PoPs and temperatures to reflect latest obs and
trends. The warm front now rests comfortably to the northeast
with the surface trough approaching the region. Additional
showers and possibly some embedded rumbles of thunder in the
Southwest Adirondacks are possible throughout the night as the
surface trough continues to push eastward. See the previous
discussion for additional details.
.PREVIOUS DISCUSSION...
The area of rain that dominated much of the region this
afternoon has decreased to mere scattered showers across the
area this evening with the heaviest rainfall embedded within
showers to the north and west of Albany. The latest SPC
Mesoanalysis indicates increasing instability mainly to the west
of the Hudson River with SBCAPE values at about 100-250 J/kg.
This aligns well with the latest HRRR that depicts SBCAPE
continuing to increase throughout the evening and into the
overnight period especially in the Southwest Adirondacks.
Speaking of the HRRR, this has been the model of choice for the
evening as other sources of HiRes guidance have struggled to
accurately resolve convection. According to the latest run,
shower activity should continue to decrease such that coverage
should become widely scattered over the coming hours. However,
maintained thunder in the forecast especially after midnight for
embedded rumbles of thunder as instability increases with almost
stagnant low temperatures and sustained elevated dewpoints. Low
temperatures overnight will primarily span the 60s with pockets
near 70 mainly in the Mid-Hudson Valley and southwest New
England.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
On Sunday, The Storm Prediction Center has placed the southeast
part of our forecast area in a slight risk for severe weather
with the rest of the area in a marginal risk. The cold front is
forecast to move from northwest to southeast across the area.
Ahead of the front the airmass will be unstable.
We expect a band of showers/thunderstorms to develop and
cross the region during the day Sunday. Heavy downpours and
gusty winds could accompany some of these storms, as instability
peaks in the afternoon with CAPES 1500-2000 J/kg and 0-6 km
shear of 40-50 KT. Damaging wind gusts will be the primary
severe threat, however can not rule a tornado or two across the
Slight Risk area given the strong shear, potentially high
instability and low LCL`s ahead of the cold front. High temps
should reach the 80s for most valley areas and 70s across higher
terrain areas. Heat indices will approach the mid 90s across
portions of the mid Hudson Valley, but look to be below heat
advisory thresholds.
A few showers and storms may linger Sunday evening over the far
southeastern areas and a few showers and storms may redevelop
over the southern adirondacks in the evening with the upper
level trough and cold pool moving southeastward.
Monday looks cooler and breezy, but with the upper level trough
overhead, a shower is possible over western New England.
Otherwise clearing and cooler for Monday with highs mainly in
the 70s.
Mainly clear and cool for Monday night, with low temperatures in
the 40s to lower 50s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Surface high pressure will be centered over the region on
Tuesday resulting in sunny, warm and dry weather. This high
will push southeastward on Wednesday resulting in a southwest
return flow of milder air. Wednesday should also remain mostly
dry. Highs will rise well into the 80s across the valleys and
the upper 70s to lower 80s in the higher elevations.
A cold front associated with an area of low pressure tracking
well northward into Quebec will slowly cross the region
Wednesday night into Thursday, Independence Day. Showers and a
few thunderstorms will likely accompany the front during this
time. There remains a bit of uncertainty with the movement of
the front. Best case scenario, the front moves through the area
early thursday leaving a mostly fair Independence Day before
the front returns northward Thursday night into Friday bringing
additional showers and storms. Worse case the front stalls over
the area with showers and storms on Independence day. Will
monitor trends over the coming days. Otherwise, it looks to be a
very warm and humid day on Thursday with heat index values
reaching the 90s in the valley areas.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Through 00z Monday...Flying conditions range from VFR
(KALB/KPOU) to MVFR (KGFL/KPSF) across the terminals this
evening due to low ceiling heights as low-level RH remains
elevated ahead of a warm frontal passage. Today`s previous area
of rain has been reduced to mere showers across the region this
evening which are currently either just outside or within the
vicinity of the TAF sites.
Throughout the remainder of the evening, scattered showers are
set to continue. Showers, especially those that contain heavier
downpours and/or those that cross KGFL and KPSF whose ceilings
are on the lower end of MVFR thresholds, will be capable of
dropping VFR/MVFR ceilings to MVFR/IFR heights. At this time,
impacts to visibility are not anticipated, though will monitor
conditions and make amendments should a heavier downpour look to
potentially cause reductions.
While the latest HiRes models indicate a fair reduction in
coverage to showers for the overnight period, the latest HRRR
indicates some light showers could cross each of the terminals
during the overnight period. These are not expected to reduce
visibility past VFR thresholds, but once again MVFR to IFR
ceilings are possible especially at KGFL and KPSF. This looks to
be most likely between 06-09z and TEMPOs were added to the TAFs
accordingly.
Shower activity should break at the terminals by daybreak,
yielding VFR to MVFR ceilings across the terminals. Tomorrow, a
period of showers and thunderstorms will be possible ahead of a
passing cold front. Included PROB30 groups to reflect this
likelihood, though uncertainty still exists pertaining to the
exact timing due to model disagreement. Will provide adjustments
in future updates.
Winds throughout the period will remain breezy out of the south
to southwest. Sustained speeds ranging from 10-15 kt with gusts
of 15-27 kt will remain possible through the evening before
decreases to sustained speeds of 6-10 kt occurr for the
overnight. Tomorrow, sustained speeds will range form 5-10 kt.
Outlook...
Sunday Night: Low Operational Impact. Breezy. NO SIG WX.
Monday: Low Operational Impact. Breezy. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: Low Operational Impact. Breezy. NO SIG WX.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Independence Day: Low Operational Impact. Slight Chance of SHRA...TSRA.
&&
.HYDROLOGY...
There is a marginal risk for excessive rainfall today and
tonight across all but Litchfield County CT. Showers will
continue to overspread the region tonight, with embedded
thunderstorms developing later today into tonight. High PWAT`s
of ~2", warm cloud depth and some potential training of
thunderstorms could lead to heavy rainfall and localized
flooding tonight into Sunday. The greatest potential for this
looks to be across the southern Adirondacks and western Mohawk
Valley for tonight, where some areas have already received over
an inch of rain.
Localized flooding of urban, low lying and poor drainage areas
is possible from any thunderstorms.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...SND
NEAR TERM...Gant
SHORT TERM...SND
LONG TERM...SND
AVIATION...Gant
HYDROLOGY...SND/KL
Area Forecast Discussion
National Weather Service Boston/Norton MA
748 PM EDT Sat Jun 29 2024
.SYNOPSIS...
A slow-moving frontal system brings two rounds of scattered
showers and thunderstorms, tonight into early Sunday morning,
and then perhaps again Sunday afternoon and evening. Passing
widely scattered afternoon showers are possible on Monday,
although drier weather prevails most of the time. High pressure
brings dry weather, seasonably warm temperatures and low levels
of humidity for Tuesday and Wednesday. While the timing is still
uncertain, turning more humid and unsettled for the Fourth of
July thru the early part of the weekend with a couple of
disturbances offering chances for clouds, showers and
thunderstorms.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
735 PM Update:
Radar imagery at this hour reflects what is amounting to very
light showers largely north and west of I-95, gradually moving
eastward. However METARs and mesonet information indicate little
if any QPF at all with this, with only a handful or so of sites
actually recording measurable precip. Did boost PoP up into the
Likely/low Categorical range at least thru midnight for most
areas, but at least through midnight, this is the textbook
"high-PoP/low-QPF" scenario that you`ll ever find. So while
radar looks imposing, there really isn`t much rain falling from
these echoes. Also backed off on the thunder mention for this
period of time.
However we think that changes for the 2nd half of the evening
into early Sun AM, but mainly for CT-central/southern RI-SE MA.
Watching a cluster of t-storms with cooling cloud tops over
eastern PA NW of the Philly area with additional re- development
over north-central PA, with both areas moving ENE in the WSW
flow aloft. For Southern New England, most models show rising
dewpoints into the lower 70s later in the overnight into the
pre-dawn hrs. With higher dewpoints at night, LCL heights are
lower and with that comes somewhat higher most-unstable CAPE
values (around 500-900 J/kg or so) mainly from HFD-IJD-PVD-PYM
southward. Convective-permitting guidance varies on the handling
of this, with the past several HRRR runs being the most bullish
in the outlined area, with more tepid/muted answers from the
WRF suite and the 18z NAM-3km. So for the 2nd half of the
overnight into early Sunday, ended up reducing PoP elsewhere to
around a chance level (25-30%) but boosted PoP to categorical
for the southern third, added mention of thunder and increased
QPF during the 06-12z Sunday period. Not expecting severe with
this but if current/new development sustains itself in this
setting, we could see overnight lightning and heavy downpours
roughly from Hartford to Providence to Cape Cod.
The rising dewpoints should also lead to more expansive stratus
development for the coastal areas, but pretty strong southerly
winds should keep fog to a minimum.
No changes to lows which look on track attm.
Previous discussion:
Showers assocd with a weak mid level shortwave and anomalous PWAT
axis are moving into northern and western MA this afternoon.
Expect a period of showers across all SNE through the evening
and into the overnight as deep moisture axis with 2-2.25" PWATs
move into the region. Marginal elevated instability develops so
can`t rule out an isolated t-storm, but the best chance may come
toward daybreak along the south coast and Cape/Islands. A few
of the CAMs are showing this potential but there is uncertainty
regarding whether the convection stays offshore or extends
further north along the south coast. Something that needs to
monitored overnight as high PWAT airmass supports heavy
rainfall. Otherwise, it will be a somewhat breezy night as
modest low level jet develops. The SW flow will bring increasing
humidity as dewpoints climb to around 70 overnight. Temps will
be nearly steady in the upper 60s to lower 70s. Stratus and
patchy fog will develop.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Sunday and Sunday night...
* A round of strong to severe t-storms possible Sun afternoon and
evening
* Damaging wind gusts are the primary threat but large hail, heavy
rainfall and also a tornado is possible
An area of showers and a few t-storms may be ongoing along the south
coast and Cape/Islands to start the day. There is lower than normal
confidence as convection could end up further south but if it does
extend along the south coast, it will move offshore by late morning.
Otherwise, stratus and patchy fog will burn off away from the south
coast leading to partial sunshine. Given warm sector airmass with
925 mb temps 22-24C, temps should reach well into the 80s to near 90
away in the interior. Stratus will likely linger into the afternoon
along the south coast with temps holding in the upper 70s with SW
flow. Oppressive humidity is likely with dewpoints reaching the low
to mid 70s. Heat indices expected to approach 95 in the CT and
Merrimack valleys.
The main forecast concern will be the potential for strong to severe
t-storms in the afternoon and evening as a strong cold approaches
from the west. The increasing forcing for ascent will likely result
in a greater areal coverage of storms. Mid level lapse rates are
marginal, but the heat and high dewpoints should make up for this
with CAPES likely reaching 1500-2500 J/kg in the interior. This
instability combined with impressive deep layer shear of 40-50 kt is
very favorable for organized storms. Given strong linear forcing
ahead of the front, storms will likely organize into line segments
or even some sort of QLCS as indicated by all the hi-res CAMs.
Damaging wind gusts will be the primary threat, but can`t rule out
large hail or even a tornado if any discrete supercells can develop.
SPC SREF showing moderate probs of STP > 1. Best chance of severe
weather will likely be north and west of I-95 due to marine layer
near the coast and CSU machine learning probs and HREF updraft
helicity are highlighting the interior for severe weather. Also
can`t rule out locally heavy rainfall and flooding from t-storms but
severe weather appears to be the greater threat.
Storms are expected after 2 pm across interior northern and western
MA, gradually reaching the south coast Sun evening. Convection
should be in a weakened state by the time it reaches the coast due
to weaker instability but strong shear may help to sustain
convection a bit longer. Showers and a few storms could linger into
the overnight period over the Cape/Islands, otherwise decent drying
will be moving into the region overnight as cold front gradually
pushes offshore with NW flow developing.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Highlights:
* Hit-or-miss widely scattered showers Mon, but most stay dry with
lowering humidity levels.
* Dry and warm but with tolerable humidity levels for Tue and Wed.
* Turning more humid and more active for the Fourth of July, and
potentially into Fri/Sat too, with clouds, showers and storms
possible. Exact timing still uncertain.
Details:
Monday:
Surface ridge associated with a seasonably-strong 1024 mb high
pressure over the Gt Lakes region eventually builds in. Will still
see generally improving conditions, although shortwave
disturbance aloft and associated cooler pool of air aloft should
produce enough if still meager instability to pop diurnal
cumulus clouds and hit-or- miss showers in widely scattered
coverage. Can`t really rule out a shower anywhere in Southern
New England, although central MA eastward has somewhat better
chances with somewhat higher surface dewpoints (lower 60s).
However not expecting washouts with these showers. Conditions
improve significantly toward drier weather by the evening both
with waning diurnal instability and passage of the shortwave
disturbance aloft, with falling dewpoints into the 50s thru
evening on northerly winds. Highs in the mid/upper 70s and lows
in the mid/upper 50s.
Tuesday and Wednesday:
500 mb heights briefly rise in this period, along with high pressure
settles in over the Northeast in this period. This high shifts
offshore later into Wed night. Leads to a couple of tranquil and
pleasant early-July days with comfortable humidity levels and highs
in the low to mid 80s.
As high pressure moves offshore late Wed evening, SW flow and
weakening 500 mb heights (upper ridge shifting east) should bring
increased cloud cover and rising dewpoints/humidity levels. Flow
aloft also strengthens a bit; ahead of a frontal system for the
Fourth of July, that preceding stronger flow aloft could bring a
canopy of cloud cover in potentially quicker than current forecast
calls for on Wed evening. Thus lows also warmer in the mid to upper
60s.
Fourth of July Holiday:
While primary weak-amplitude disturbance aloft in fast westerly flow
passes to the north into Quebec/northern New England, the Fourth of
July is looking active as a sagging cold front moves southeast
through New England. This front should act on an increasingly humid
air mass to favor showers and t-storms. Greatest uncertainties at
this time lie in the timing and how warm/degree of instability, and
kept PoPs pretty broadly in the Chance range for now and then re-
assess once there is better clarity on each of those. But as it
looks now it does look like Thurs and potentially into Thurs night
features clouds and showers/storms. With dewpoints in the upper 60s
to mid 70s, it should also be quite humid. Kept highs in the mid 80s
for now as well, although clouds and shower/storm coverage will
dictate adjustments to highs as well. Lows in the mid to upper 60s.
Friday and Saturday:
Forecast for Fri is uncertain as there looks to be another
disturbance aloft which tries to send a warm front back into
Southern New England either Fri or Fri evening/Sat. GFS is the
quickest in progressing this feature into our area into Fri, while
the ECMWF/Canadian GEM and its ensembles are slower, more into Sat.
Kept PoP pretty broadly into the Chance range here given the
uncertainties which are close to NBM values; these too will also
need to be adjusted pending trends in subsequent guidance.
&&
.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update:
Tonight: Moderate confidence.
Conditions gradually deteriorate from VFR to VFR/MVFR levels
through midnight for most, with more degraded/MVFR-IFR more
likely for the southern TAFs. Current area of -SHRA are light
and not restricting visby and expect that to continue. The
exception is after 06z with the risk for +SHRA/TSRA from HFD-
IJD-PVD-PYM southward into the Cape and Islands. Risk for
lightning and localized downpours for these areas. Can`t rule
out a shower north of these areas but not expecting much north
of this line. SSW winds around 10-15 kt with gusts 20-25 kt.
Sunday...Moderate confidence.
Conditions improve to VFR interior by 16z. However, IFR may
linger through the afternoon along the south coast. SW gusts to
20-25 kt. Showers and possibly a few t-storms should be exiting
the Cape/Islands in the morning. Then another round of
showers/t-storms expected to develop after 18z in the interior,
reaching the south coast in the evening. A few strong to severe
storms possible with damaging wind gusts the primary threat.
Sunday night...Moderate confidence.
IFR with showers/t-storms in the evening along the south coast,
then improving to VFR overnight. Wind shift to NW 00-06z.
KBOS TAF...Moderate confidence in TAF. Generally OVC VFR with
P6SM -SHRA, with deterioration to at least MVFR ceilings
overnight. Improving to VFR around 16z Sun with another round
of showers/t-storms after 20z. SSW winds around 10-15 kt with
gusts 20-24 kt.
KBDL TAF...Moderate confidence in TAF. MVFR cigs lowering to IFR
this evening as light showers move across the region. Low risk
for embedded thunder after 06z. Improving to VFR by 15z Sun
with another round of showers/t-storms after 20z.
Outlook /Monday through Thursday/...
Monday: VFR. Breezy. Slight chance SHRA.
Monday Night through Tuesday Night: VFR.
Wednesday: VFR. Breezy.
Wednesday Night: VFR. Breezy. Chance SHRA.
Independence Day: Mainly VFR, with local MVFR possible. Breezy.
Slight chance SHRA, slight chance TSRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Through Sunday night...High confidence.
Gusty S winds tonight becoming SW on Sunday with gusts to 25 kt at
times. SCA continued for all waters. Winds shift to NW overnight Sun
night behind the cold front. Vsbys reduced in developing showers and
fog tonight, with fog lingering on Sunday especially south coastal
waters. A few t-storms possible over southern waters late tonight
and Sun morning, then more showers and t-storms moving across the
waters late Sun and Sun night.
Outlook /Monday through Thursday/...
Monday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Slight chance of rain showers.
Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft.
Tuesday through Wednesday: Winds less than 25 kt.
Wednesday Night: Winds less than 25 kt. Slight chance of rain
showers.
Independence Day: Winds less than 25 kt. Seas locally
approaching 5 ft. Slight chance of rain showers, isolated
thunderstorms.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 AM EDT Sunday for ANZ230-236-251.
Small Craft Advisory until 8 PM EDT Sunday for ANZ231-250.
Small Craft Advisory until 11 PM EDT Sunday for ANZ232>235-237.
Small Craft Advisory until 6 AM EDT Monday for ANZ254>256.
&&
$$
SYNOPSIS...KJC/Loconto
NEAR TERM...KJC/Loconto
SHORT TERM...KJC
LONG TERM...Loconto
AVIATION...KJC/Loconto
MARINE...KJC/Loconto
Area Forecast Discussion
National Weather Service State College PA
1158 PM EDT Sat Jun 29 2024
.SYNOPSIS...
A cold front will push through central Pennsylvania on Sunday.
A large high pressure system will build into the region early
in the upcoming week, followed by a dying cold front pushing in
from the Great Lakes and stalling out over the area late next
week by the middle of next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
Lingering convection over parts of the south central and
southeast late this evening should continue to decrease in
coverage after midnight. Can`t drop POPs altogether overnight as
850 mb thermal ridge is overhead and additional isolated showers
can still pop up overnight, but most areas will remain dry. We
expect there to be areas of fog give current dewpoint depressions
of 1-3F and dewpoints in the lower 70s. Some areas of fog are
very likely given high surface dewpoints and light winds ahead
of the cold front that will be approaching from the GLAKS and
Ohio Valley overnight. With thermal trough in place and 850
temps around +18 to +19 across much of central PA, lows tonight
will be warm, ranging from the mid 60s to mid 70s, which is
10 to 15 deg F above normal for late June.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH 6 PM SUNDAY/...
Passage upstream surface cold front will bring the chance for
another round of convection Sunday. Locations most likely to see
potential strong/svr t-storms are over the southeastern part of
the CWA due to a fropa coinciding with peak heating of the late
afternoon.
Max temps Sunday will be a few to several deg F higher than
today (Sat) in all locations.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Dewpoints drop off rapidly by Sunday evening with another
comfortable few days of weather in store to start the month of
July. Canadian high pressure builds to southern Ontario by
Monday night, bringing a fair and cool night with the high
moving directly overhead. This will result in efficient
radiational cooling and min temps several degrees below normal.
Fair and warmer weather is expected Tuesday into at least the
first half of Wednesday, as upper level ridging builds over the
state and surface high drifts offshore.
All medium range guidance tracks a weakening shortwave well
north of PA late Wednesday into Thursday. The dying cold front
is likely to sag into the state Thursday and stall out in the
vicinity of PA through Friday. Falling heights/surging low level
moisture ahead of the front could support scattered convection
as early as Wednesday afternoon over the northwest half of PA.
However, a better chance of showers/tsra areawide will come
with the arrival of the front Thu into Friday. Early best guess
of late week rainfall based on ensemble plumes ranges from 0.25
to 0.75 inches, with the highest amounts over the N Mtns and
least in the south.
Heat and humidity should peak ahead of the front Wed-Thu.
Ensemble mean 850mb temps surging to near 20C indicate max temps
could reach the low to perhaps mid 90s in the Lower Susq Valley
Thursday, with high humidity pushing heat indices into the mid
and upper 90s. Ensemble plumes suggest slightly cooler daytime
temps late week, due to more clouds/showers. However, high pwats
in the vicinity of the stalling front should result in muggy
nights and above normal min temps the entire second half of next
week.
Models begin to diverge as we head into the weekend. Most
guidance suggests that rain chances stick around through at
least Saturday as another cold front approaches the area.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
A few more adjustments made just before I sent the 00 TAF
package. Main thing was to add in some VCSH early on, as
the airmass is supporting a few showers forming since
about an hour ago.
Earlier discussion below.
Adjusted TAFS several times this afternoon and early this
evening, as line of storms that formed over the mountains
earlier this afternoon have been moving along at a rather fast
pace. Still concern that the far southeast activity may slow
some, given the southeast flow and very high dewpoints in place
now.
Main change to the 00Z TAF package was to back off on
showers overnight, and put showers in toward Sunday morning,
given location of main cold front and upper level forcing.
Still expect conditions to improve later Sunday, as the winds
shift to the northwest and much less humid air moves into the
area from northwest to southeast.
Monday and Tuesday look dry at this point with a dry airmass
and VFR conditions, as high pressure builds into the area.
A bit breezy on Monday, given the cooler air being advected
into the region.
Outlook...
Mon-Tue...Dry weather with VFR conditions except perhaps some AM
valley fog N.
Wed...PM TSRA moving across from W-E.
Thu...A chance of showers and storms.
&&
.HYDROLOGY...
Over half of an inch of rain last night and this morning over
the far NW has increased confidence that the precip in the N
will be very efficient today. While dbZ and the amt of ltg may
not impress today, the moist adibatic profiles and deep warm
layer will make for heavy rain at times. Draw back to fast storm
motions: 1) radar may underestimate precip as the fast cells
skip along in between scans, and 2) it`s tough to get flooding
when the cells have a low residence time. However the repeated
showers/storms could (easily) overcome that issue.
Prev...
The area of greatest concern for heavy rain and flash flooding
will spread south and east later this morning through this
afternoon as the axis of the LLJ slides east and the favorable
RR quad of an approx 2 sigma upper level jet and its enhanced
MESO-B lift moves overhead.
PWAT values increased steadily from west to east overnight from
a little over one inch to start the night to around 1.6 inches
early today.
PWATS via the GEFS will peak around +3 sigma or about 2.25
inches later this morning through this afternoon (which are
values that haven`t been seen so far in PA during 2024). This
anomalous, deep moisture will support the threat for locally
very heavy rain (in excess of 2 inches/hour) within a broad
area of 1 to 1.5 inch basin average storm total rain forecast
for much of Central and Northern PA. Issued a Flood Watch from
12Z today through 06Z Sunday for much of Central and Northern
PA where FFG values are well under 2 inches/3 hours across
parts of the Northern Mtns.
&&
.CLIMATE...
At the Altoona Airport, a record rainfall of 0.76 inches was
set today. This total breaks the old record of 0.53 inches set
back in 1972.
Through 6/27,June ranks as the second warmest on record at
Harrisburg with an average monthly temperature of 76 degrees or
+3.8 degrees above normal.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Lambert/DeVoir/Fitzgerald
NEAR TERM...Lambert/DeVoir/Fitzgerald/Dangelo/Martin
SHORT TERM...DeVoir/Fitzgerald/Steinbugl
LONG TERM...DeVoir/Fitzgerald/Bauco
AVIATION...Martin
HYDROLOGY...Lambert/Dangelo
CLIMATE...Evans/Steinbugl
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
608 PM MDT Sat Jun 29 2024
...New AVIATION...
.SYNOPSIS...
Issued at 200 PM MDT Sat Jun 29 2024
Daily thunderstorm chances will continue throughout the entire
period with Wednesday showing the highest probability for showers
and thunderstorms. Temperatures will run near or a few degrees
above normal.
&&
.DISCUSSION...
Issued at 200 PM MDT Sat Jun 29 2024
The monsoonal pattern is well established with the presence of the
summertime subtropical ridge. The location of this ridge will be
what drives our weather for the period, and really the remainder
of the summer. Starting off, it`s centered over the DFW area, but
with a ridge axis extending well to its west (and east), reaching
into our CWA. This pattern has worked to bring warm temperatures
aloft along with some subsidence as well as import drier air.
PWats were around 1.2" on this morning`s EPZ sounding. Satellite
and radar are relatively quiet as of 1PM with just a few showers
over the Gila and Sacs as thermodynamics and dynamics are
presently limited thanks to the high. With that said, however, an
easterly push is expected to arrive this afternoon, moving east to
west, which will likely aid in thunderstorm development by adding
some low-level lift though isolated to maybe scattered coverage is
expected. Air mass wise, moisture and temperature (or in terms of
theta-e) advection will be fairly neutral, at least initially.
Temperatures for Sunday will be around 5 degrees cooler in spite
of the ridge continuing to nudge westward. The HRRR is showing an
uptick for thunderstorm coverage for tomorrow in spite of the
cooler temperatures. An easterly wave over Mexico was over
Southern Chihuahua as of typing this discussion with a trailing
vort max arcing toward the Rio Grande Valley of TX. The bulk of
this easterly wave looks to continue into the Pacific according to
the GFS, but the GFS and NAM show the trailing vort tube and
moisture forced northward into the CWA, which if true, would
provide subtle DPVA.
As we head into Monday, the ridge will begin making a slow trek to
the east while ridging strengthens off the Pacific Coast. For
Monday and Tuesday, temperatures will climb some as today`s air
mass retreats east while thunderstorm chances follow their usual
preference toward the mountains with at least isolated coverage
spreading into the lowlands. On Wednesday, the ridge moves far
enough east, a weakness/trough develops over NM between the
Pacific Ridge and subtropical ridge over the CONUS. Moisture will
center within this weakness, giving our entire CWA its best chance
for precipitation of the period. GFS shows PW values over 1.5"
while the ECMWF shows dew points in the mid 50s. Heavy rain and
flash flooding would be the main concern.
Drier air will try and push in from the northwest beginning
Thursday with models disagreeing on how far south it will go. The
other important thing about NW-flow is it opens the door for
disturbances to directly impact our CWA either via frontal pushes,
which is hinted at for next Saturday or DPVA, which usually stems
from features too subtle for models to pick-up this far in
advance. All that said, thunderstorm chances will continue as we
finish out the work week while temperatures hover near or just
above average. Looking at NBM temperatures for KELP, the spread
between the 25th and 75th percentile is as much as ten degrees by
next weekend, indicating the uncertainty of how much cooler air NW
flow will allow to push into Southern NM and Far W Texas.
&&
.AVIATION...
(00Z TAFS)
Issued at 557 PM MDT Sat Jun 29 2024
Thunderstorms are moving from the east to the west across the
region. The threat for thunderstorms at KELP has ended and will
end shortly for KLRU, but the threat for thunderstorms and strong
thunderstorm winds will continue for the next few hours for KDMN
and KTCS. Later the winds will slow and our ceilings will become
unlimited by 10 PM. Winds will generally be light from the east
tonight, but the low end east or southeast winds gusty winds will
return on Sunday. Like today there will be another threat for
afternoon and evening thunderstorms across the area, but the
confidence right now of it impacting a certain airport is not
high, so I have not mentioned the threat is the round of TAF`s.
&&
.FIRE WEATHER...
Issued at 200 PM MDT Sat Jun 29 2024
Minimal fire concerns continue as we remain in a monsoonal
pattern. Temperatures are not expected to be as hot for Sunday,
which will allow for higher min RH values in the afternoon, only
falling into the mid 20s. Winds will remain light. Thunderstorm
development is expected again tomorrow afternoon with the HRRR
showing an increase in coverage than seen the past two days.
Regardless, convection will be favored in the mountains. The main
concern with any storm will be gusty winds. Thunderstorm coverage
and chances will decrease some for Monday and Tuesday before
increasing again Wednesday. Venting will range very good to
excellent for Sunday and good to very good for Monday.
&&
.PRELIMINARY POINT TEMPS/POPS...
El Paso 82 102 81 101 / 30 30 50 10
Sierra Blanca 71 94 69 94 / 20 30 20 10
Las Cruces 76 99 74 99 / 60 30 60 20
Alamogordo 69 96 70 96 / 30 20 30 10
Cloudcroft 52 73 53 72 / 30 30 30 30
Truth or Consequences 75 95 73 94 / 60 20 60 40
Silver City 68 90 66 88 / 70 40 80 60
Deming 75 98 72 96 / 70 30 80 30
Lordsburg 73 97 71 94 / 70 40 90 50
West El Paso Metro 79 99 78 98 / 40 30 50 10
Dell City 73 98 72 98 / 10 20 20 10
Fort Hancock 77 101 74 101 / 20 30 30 10
Loma Linda 71 93 70 91 / 20 30 40 10
Fabens 79 100 76 100 / 20 30 40 10
Santa Teresa 77 97 74 96 / 40 30 60 20
White Sands HQ 77 96 76 96 / 40 20 50 20
Jornada Range 73 96 71 95 / 50 20 60 20
Hatch 73 98 71 97 / 60 20 60 30
Columbus 76 97 73 96 / 70 30 80 20
Orogrande 75 96 73 96 / 30 20 40 10
Mayhill 57 84 58 84 / 30 40 20 30
Mescalero 57 85 58 83 / 30 30 30 30
Timberon 56 82 55 82 / 20 30 30 20
Winston 63 86 61 84 / 60 30 70 70
Hillsboro 70 92 68 91 / 70 30 70 60
Spaceport 70 95 68 94 / 60 20 60 30
Lake Roberts 63 90 62 86 / 60 40 80 70
Hurley 69 93 66 91 / 70 30 80 50
Cliff 68 99 66 96 / 60 30 80 60
Mule Creek 69 93 67 89 / 60 40 80 70
Faywood 70 91 68 89 / 70 30 80 50
Animas 70 97 69 94 / 70 50 80 50
Hachita 70 96 69 95 / 80 40 80 40
Antelope Wells 69 95 68 94 / 80 70 90 50
Cloverdale 65 90 66 89 / 80 70 80 50
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 6 AM MDT Sunday for TXZ418-419-423-424.
NM...Heat Advisory until 6 AM MDT Sunday for NMZ407-410-411-427>429.
Flood Watch until midnight MDT tonight for NMZ415-416.
&&
$$
FORECASTER...15-Brice
Area Forecast Discussion
National Weather Service Goodland KS
946 PM MDT Sat Jun 29 2024
.KEY MESSAGES...
- Low confidence with regard to thunderstorm development
tonight and Sunday night.
- Much cooler highs Sunday due to cloud cover all day.
- Hot weather returns Monday behind a warm front. However highs
are not as hot.
- Chances for storms each day, mainly during the evening.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 216 PM MDT Sat Jun 29 2024
Latest upper air analysis shows nearly zonal flow over the
central Plains. Pockets of higher water vapor were moving
through this flow, leading to cloud cover. At the surface winds
were breezy from the northeast. A surface high pressure was
located over Wyoming.
For the rest of the afternoon the surface high pressure will
slide southeast across Nebraska, causing the winds to turn to
the southeast. As the high pressure approaches winds will
decline.
This evening a weaker upper level short wave trough will move
over the forecast area from the west. The latest model runs have
slightly delayed the arrival of the upper level short wave
trough. (This is in line with the delayed trend in storm arrival
of the last few days.)
Models are now keeping the cold front well south of the
forecast area during the night. However the low level jet will
strength over the front and into the forecast area. This will
provide low level moisture advection ahead of the approaching
upper level short wave trough. Both the NAM and RAP models are
suggesting elevated instability will be present with in this
part of the forecast area. In addition there does look to be a
weak LLJ nose over the southern part of the forecast area. Am
thinking scattered storms should form ahead of the approaching
upper level short wave trough around midnight, then gradually
spread east-northeast ahead of the short wave trough. Storms
will be moving around 15 MPH, which may lead to heavy rainfall
given the precipitable water values of over an inch in that part
of the forecast area. The storm activity may last well into
Sunday morning.
At this time confidence for severe weather occurring over the
southern part of the forecast area is low (30%). This is due to
the midlevel lapse rates being around 6C/km and deep layer shear
being 25-30kts. Strong thunderstorms seem more likely in this
environment. If severe thunderstorms were to form, quarter size
hail would be the main threat. The highest elevated instability
will be around midnight. This threat area may shift north or
south, however the latest model run has shifted the elevated
instability south.
Meanwhile the continued moisture advection from the LLJ will
bring in low clouds from the south. These will start from the
CO/KS border then gradually expand eastward through the
overnight hours. The surface high over Nebraska will also aid in
advecting moisture over the forecast area.
Sunday morning the upper level short wave trough will continue
to move across the southeast part of the forecast area. Elevated
instability will continue to decline. Storm activity should be
east of Graham County by noon, if not before.
Sunday afternoon an upper level short wave ridge will move in
from the west. By this time the surface high pressure will be
Central Nebraska into Central Kansas. Moisture advection will
continue. Soundings show atleast a broken, if not overcast cloud
deck over the forecast area through the day. The exception will
be East Central CO where the moisture advection will be less,
allowing the clouds to break up during the afternoon. Lowered
highs a few more degrees for the afternoon, mainly east of CO.
The 25th percentile high temperature forecast is in the low/mid
70s for this part of the forecast area. Based on this the
current forecast seems representative.
Sunday night another upper level short wave trough will move in
from the west. By this time the ridge has shifted more to the
west, pushing the upper level flow slightly more to the north.
During the evening there may be some low level convergence from
the LLJ over the northwest part of the forecast area as the
short wave trough moves through. This convergence then shifts to
the northern part of the forecast area, moving with the upper
level short wave trough. Models show deep layer shear of 40 kts
and midlevel lapse rates around 7C/km. The current data supports
the potential for storms to become severe given the elevated
instability could occur. However, the elevated instability is
highly dependent on how warm will 800- 700mb layer be and how
high will the dew points be in that layer. The HREF has not
strong storms in the forecast area at this point. For now this
bears watching as strong to severe elevated thunderstorms could
occur. However confidence is low (20%) for them to occur given
how much could change with the small details regarding the low
level temperature and moisture advection.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 216 PM MDT Sat Jun 29 2024
Monday the front will move back through as a warm front. Models
have shifted the upper level ridge slightly more to the east.
This move has also shifted where the dome of hottest
temperatures will be, resulting in highs not being as hot for
the forecast area. Heat index values are now around 100F instead
of 105F. During the latter part of the afternoon a stronger
upper level short wave trough will move into the forecast area
from the west. Midlevel lapse rates sharply decline behind the
trough, suggesting there maybe a narrow window for strong to
severe thunderstorms to form.
Monday night the storm activity will move east across the
forecast area. A band of frontogenesis accompanies the trough
across the forecast area, mainly over the northern half of the
forecast area. As such, have the best chances for rainfall
there.
Tuesday through Saturday evening chances for rainfall each day
are forecast as upper level short wave troughs move over the
forecast area. The upper level ridge will shift west and become
centered over the Desert Southwest. This will shift the storm
track to be from the northwest over the forecast area. Rainfall
chances during this timeframe seem high, which may be due to the
monsoonal moisture moving over the forecast area. Wouldn`t be
surprised if the rainfall chances end up lowering as we move
through the week.
Due to the ridge ridge shifting west of the forecast area,
highs will not be as hot. The coolest temperatures are Friday
when a stronger upper level short wave trough rounds the ridge
and brings a cold front with it.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 945 PM MDT Sat Jun 29 2024
GLD: VFR conditions will prevail this evening/overnight. MVFR
ceilings are anticipated to rapidly develop around or shortly
after sunrise (~12-14Z). Deterioration to IFR is expected
thereafter, during the mid-late morning. While some improvement
to MVFR is expected during the afternoon, ceilings will likely
deteriorate to IFR-LIFR around or shortly after sunset Sunday
evening, near the end of the TAF period. Easterly winds at
7-13 knots (this evening) will gradually veer to the SE
(overnight) and SSE (Sunday morning).. increasing to 15-25 knots
during the day.
MCK: VFR conditions will prevail this evening/overnight.. and
through much (or all) of Sunday morning. Borderline VFR-MVFR
ceilings (~2500-3500 ft AGL) are anticipated to develop by early
afternoon (~16-19Z) and persist throughout the day. Ceilings
will likely deteriorate to low-end MVFR or IFR a few hours
after sunset Sunday evening, near the end of the TAF period.
Easterly winds at 6-12 knots (this evening) will gradually veer
to the SE (overnight) and SSE (Sunday afternoon).. increasing
to 15-20 knots by mid-late afternoon.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...Trigg
LONG TERM...KMK
AVIATION...Vincent
Area Forecast Discussion
National Weather Service Gray ME
742 PM EDT Sat Jun 29 2024
.SYNOPSIS...
A warm front will bring a period of rain with a few embedded
thunderstorms to the region tonight before a potent cold front
arrives Sunday afternoon bringing the potential for strong to
severe thunderstorms. High pressure arrives early next week
with dry weather and seasonable temperatures expected for the
first half of next week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
730 PM Update...Little change to the going forecast for the
evening as as back edge to steadiest rainfall moving out.
However, convective showers and islolated thunderstormns
currently over Upstate NY will likely move ino western zones in
a few hours. Otherwise, cloudy and breezy.
High Impact Weather Potential: A few downpours are possible
overnight as well as an isolated thunderstorm though the threat
for widespread flooding and severe weather is low.
Pattern: Early afternoon water vapor imagery shows a potent
shortwave dropping through the western Great Lakes with a plume
of mid level moisture pushing into the northeastern United
States. Beneath this plume...a warm front is slowly advancing
through NY/PA with a broad region of light to moderate rain fueled
by increasing moisture and a 50kt southwesterly LLJ. Forecast
concerns for tonight center on rainfall potential as the surface
warm front lifts through the region.
Through this evening: Rain is overspreading the region from west to
east and this will continue through the evening hours with clouds
lowering. SE NH may escape meaningful rainfall through 8pm...but
elsewhere conditions will turn wet. Temperatures won/t really move
much...largely sitting in the 60s across the area.
Tonight: Warm front lifts north and east through the region tonight
with 2" PWAT plume overhead this evening gradually shifting east of
the area by daybreak Sunday. While isentropic ascent up the frontal
surface in the presence of some weak elevated instability will be
sufficient to support rainfall...broader scale forcing appears
rather lackluster through the overnight with +DPVA mostly
brushing the international boarder with some weak height falls
overhead and some jet entrance support. Overall this suggests
occasional showers through the overnight...with the greatest
threat for a few downpours being over the mountains where the
synoptic scale forcing is best. From a hazard perspective...the
threat for flooding appears rather low...but nonzero given the
deep moisture/warm cloud depths. A mild night is in store given
continued warm air advection with lows falling into the mid 50s
in the mountains with 60s to the south.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
High Impact Weather Potential:
* Slight Risk of Severe Thunderstorms
* Primary threat: Damaging Wind
* Secondary threats: Localized flooding...hail and an
isolated tornado
* Timing: 12pm-7pm
Pattern: Low pressure north of northern New England will move
north and east during the day with a cold front over western New
York as a positively-tilted shortwave and region of mid level
height falls pushes just north of the region through the day.
Our forecast focus will be on severe convective potential as the
surface cold front crosses the area Sunday afternoon. Also
watching heat indices across southern NH which may make a run at
advisory thresholds ahead of the front.
Sunday: Shortwave rotating through the positively-tilted longwave
trough races just north of the region through the day with 70kt H5
speed max moving overhead in tandem with right entrance region to
120kt upper level jet. Should see some sun in the morning as we
move into the warm sector ahead of the cold front but
convection may already be ongoing across western New
York...strengthening as downstream instability strengthens. By
early afternoon convection will likely reach the mountains of NH
as well as the CT Valley with the mesoscale guidance favoring
the potential for one line of storms closer to the beset mid
level forcing moving from northern NH ESE through the Capitol
region of ME with another line moving across southern NH where
the best instability will be located and will be downstream of
the most likely location for morning convection.
Here/s a run through the convective parameters....
Instability: Sizable disparity in the guidance here with the
NAM nest and the HRRR in their typical wetter/drier
camps...respectively. Looking at upstream llevel moisture...a
compromise is likely best which favors 1500 J/kg of MLCAPE in
southeast of the mountains as surface dewpoints push just above
70.
Shear: 40kts in the 0-3km layer with 60kts in the 0-6km layer.
Hodographs are fairly straight and parallel to the approaching
frontal boundary. Expect initial cells to grow into lines with
bowing segments likely given ample 0-3km shear. Within these bows
would be the best potential for a spin up.
Lapse rates: Decent in the H8-7 layer, but weaker /around 6C/ in the
H7-5 layer. Sufficient to support deep convection through the
afternoon.
Overall...this lines up well with the SPC outlook for damaging winds
posing our greatest severe weather risk with hail and an isolated
tornado lesser...but non-zero threats.
T8s pushing to +18C should allow highs to reach near the 90F mark
given sufficient sun. This...in addition to dewpoints moving above
70 will allow a few spots in southern NH/SW ME to approach heat
advisory levels...but not high enough or long enough to warrant any
headline issuance today.
Sunday Night: With the surface cold front near the coast to begin
the period...expect any convection to quickly be exiting the region
with mesoscale guidance suggesting a few showers along a secondary
trough/cold front that crosses the region overnight. Best potential
for these overnight will be in the mountains with at least partial
clearing elsewhere. Cold air advection will push T8s back into the
upper single digits by daybreak Monday with lows to fall into the
50s in the mountains and lower 60s elsewhere.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
At 500 MB across NOAM and environs we still a pattern that
gradually favors warmer and more humid conditions, although
nothing that I would call hot through next week. We will near
the boundary of the sub-tropical over the Atlantic and the jest
stream to our N, so we can expect some rounds of SHRA/TSRA, but
no significant widespread events.
However, on Monday we will start off less warm, but still not
out of ordinary summer temp ranges. There is a little
convergence in central and S NH as NE flow runs into a bot of
dead flow over S New England, so will see more clouds here, and
maybe a couple showers Monday afternoon, but I think this area
Is still partly sunny, with mostly sunny skies to the N and E.
Highs will mostly be in the 70s.
Monday night will be the coolest of the stretch with clearing
skies and light winds. Expect lows in the upper 40s in some mtns
pots and generally low to mid 50s elsewhere. Tuesday looks
mainly sunny and dry with low humidity, as high pressure crosses
the region, and highs 80-85, but cooler along the mid-coast.
Flow shifts SW as the sfc high shifts offshore, and the
resultant return flow will bring in more humid conditions.
Wednesday looks mainly dry though, but with partly sunny skies
and highs 80-85 once again.
A weakening cold front moves in from the NW Wed night, and
loses its steam over the CWA, so some SHRA and maybe some TSRA
are possible Tue night into early Thursday, but expect clearing
skies and warm and humid conditions on Thursday.
Weak high pressure moves in for Friday, so its be dry, but
still warm and humid. Next weekend remains uncertain as we sit
beneath weakly anticyclonic flow and troughing to our W, which
the means the potential waves and rounds of convection, but it
should stay on the warm and humid side.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Short Term...
Summary: Deteriorating conditions expected through tonight as a warm
front crosses the region with showers and a few embedded
thunderstorms. Showers end Sunday morning...with another round of
showers and strong to severe thunderstorms in the afternoon before
partial clearing Sunday night.
Restrictions: MVFR CIGS are building across the terminals this
afternoon as showers arrive from the west. Expect deterioration to
IFR or low MVFR this evening and overnight with low CIGS and
some fog development. Improvement to VFR is expected on Sunday
morning with showers/thunderstorms bringing additional
restrictions in the afternoon. Some fog development is possible
HIE/LEB Sunday night with restrictions possible here.
Winds: Southerly winds 10kts will continue through tonight before
shifting southwest and increasing to 12g18kts for the day Sunday.
Winds turn northwest less than 10kts behind the cold front Sunday
night.
LLWS: Southwesterly winds in the 1.5-2kft layer strengthen to 40-
50kts with LLWS expected overnight tonight. This will end Sunday
morning with no additional LLWS through Sunday night.
Lightning: Very isolated thunderstorms are possible for the
overnight. On Sunday...chances for thunderstorms increase for the
afternoon with the potential for thunder throughout the terminals in
the 18Z-00Z timeframe. Some of these storms could be strong to
severe with damaging winds. No lightning is expected Sunday
night.
Long Term...VFR expected Monday through Wed, with possible
valley fog Monday night. Then more widespread flight
restrictions possible Wed night into early Thu in SHRA/TSRA and
some fog.
&&
.MARINE...
Short Term...SCA conditions due to both winds and waves are
expected to continue through Sunday ahead of an approaching cold
front. Winds shift slowly shift northwesterly and diminish
Sunday night...though residual SCA waves will likely persist
through the first half of the night.
Long Term...Generally light flow is expected through the middle
of the week with winds and seas staying below SCA levels, but it
could pick up some Wed night or Thu.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 11 PM EDT Sunday for ANZ150>154.
&&
$$
SYNOPSIS...
NEAR TERM...Arnott/Ekster
SHORT TERM...Cempa
LONG TERM...Cempa
AVIATION...
MARINE...
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
903 PM CDT Sat Jun 29 2024
.KEY MESSAGES...
- There is a 20 percent chance for thunderstorms south of I-72
late this evening. The strongest of the storms will pose a risk
for locally strong wind gusts and heavy rain leading to ponding
of water in urbanized areas.
- Seasonably hot and humid conditions make a return Wednesday-Friday
with heat indices likely (50-70%) reaching 100 degrees or
greater for locations south of I-72 on Wednesday.
- Multiple chances for thunderstorms also return with a 40-50%
chance on Wednesday and a 60-70% chance on Thursday. Outdoor
activities could be impacted, especially due to the threat of
lightning.
&&
.UPDATE...
Issued at 902 PM CDT Sat Jun 29 2024
A cold front was located across central IL from around Danville
to Jacksonville as of 8 PM slowly migrating southward. The central
IL portion of the frontal zone is becoming increasingly inactive
with respect to thunderstorms, however around 3000 J/kg MLCAPE
instability and 30 kt effective bulk shear was located ahead of
the front according to RAP-based analysis. More pronounced
disturbances along/ahead of the front from OK into MO, as well as
KY into OH while lift was lacking across central IL, however
likely contributing to the lack of thunderstorm activity here.
Nevertheless, high resolution models continue to advertise at
least isolated activity through midnight so have maintained slight
chances south of I-72, shrinking down south of I-70 by midnight.
Otherwise, cooler lows ranging from 56 in Galesburg to 70 in
Lawrenceville look on track for tonight, with winds becoming
northerly around 10 to 12 mph with gusts to 20 mph.
37
&&
.SHORT TERM... (Through Late Sunday Night)
Issued at 257 PM CDT Sat Jun 29 2024
Our morning thunderstorms have now departed to Indiana, with a bit
of capping building in their wake to limit convective potential for
at least the next couple hours. however, given 2500-3500 J/kg MLCAPE
(highest across our northeast) and PWATs near/over 2 inches per
SPC`s mesoanalysis, water-laden microbursts capable of torrential
rain, small hail, and especially localized damaging wind gusts
remain a concern through evening with the strongest cells that
develop along the southeastward-moving cold front currently situated
near the I-55 corridor. This front will become more organized as it
surges southward late this evening, bringing a sharp gradient (and
rapid change with time at any given location) in theta-E (nearly 1
degK/km) and uptick in northwest winds which could gust close to 30
mph. Went with a blend of HRRR and NBM for overnight lows, which are
forecast to fall into the 50s northwest of the Illinois River but
remain close to 70 south of I-70 where the front will not arrive
until between roughly midnight and 3 am.
The continued cool advection will prevent temps from rising above
the 70s tomorrow for most, if not all, of the CWA, making it feel
more like mid May than late June and offering a much needed reprieve
from the oppressive humidity. Temps dip further tomorrow night as
winds drop off and in the absence of clouds radiational cooling is
optimized. Around 60-80% of HREF membership brings Monday morning
lows into the 40s outside of urban areas, though NBM, which is
calibrated to climatology, suggests those chances are closer to
10- 20% with the ensemble mean in the low 50s; we`re going to
maintain forecast lows closer to NBM mean for now, but wouldn`t be
surprised if we wind up on the cooler side of things if
tomorrow`s highs don`t overachieve (which sometimes happens with
so much sunshine) and we wind up with both as little wind and as
few clouds as currently forecast.
Bumgardner
.LONG TERM... (Monday through Next Saturday)
Issued at 257 PM CDT Sat Jun 29 2024
On Monday, a mid to upper level ridge will be centered over the area
with its associated surface high over the Great Lakes region. This
will lead to a clear, calm, and somewhat chilly start to Monday with
temperatures in the low 50s to upper 40s, while highs will only
reach the upper 70s Monday afternoon. As the mid to upper level
ridge axis passes through, our area will return to a deep southerly
flow regime, leading to the return of summertime heat and humidity
by Tuesday. A vast majority of the LREF guidance depicts the center
of this ridge (with 500mb heights of 596dm) settling over the SE
CONUS next week, placing our region on the northern edge where waves
of shortwave energy will traverse.
A weak upper level trough will pass along the northern Great Plains
and deamplify as it progresses eastward just north of our region on
Wednesday. The shortwave energy and its attendant, weak, cold front
approaches from the NW on Wednesday, bringing with it the next
chance for some rain, especially in the northern portions of the
area where there is more sufficient column moisture present. Some of
the deterministic model guidance depicts this weak cold front
stalling out near our area Wednesday into Thursday, likely due to
the 596dm ridge to our SE keeping the front from progressing to the
SE of our region. The stalled front will essentially act as a runway
for any waves of precip or convection that traverse around the 596dm
ridge, potentially leading to flooding concerns depending on where
this sets up at on Wednesday. Wednesday still appears to be the
warmest day next week with highs in the lower 90s and heat indices
nearing 100 degrees south of I-72, where the later frontal passage
is at. However, high temps on Wednesday will be highly dependent on
the exact timing of this weak cold front, which at this time is
uncertain.
Perhaps the better and more widespread chance of rain will be on
Thursday (the 4th of July) as shortwave energy pivots around the
596dm ridge into the CWA, resulting in likely PoPs for most of the
area. Uncertainty regarding the strength and position of the strong
ridge remains after Thursday next week as an upper level trough may
dig into the Upper Midwest, potentially deamplifying the upper
level ridge. Regardless, our current forecast has highs in the 80s
and lows in the 60s, but given the current ensemble spread there
is low confidence this far out.
Peine
&&
.AVIATION... (For the 00z TAFs through 00z Sunday Evening)
Issued at 637 PM CDT Sat Jun 29 2024
A cold front will press south of KSPI-KDEC-KCMI by 01Z, with
associated showers and thunderstorms ending to the north of this
front. Skies will gradually clear this evening, with VFR
conditions expected through 00Z Monday. Winds becoming N-NW 8-14
kts with gusts 20-25 kts by 01Z-02Z, then gusts diminishing by
06Z-12Z.
37
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Louisville KY
847 PM EDT Sat Jun 29 2024
.KEY MESSAGES...
* Very warm and muggy this afternoon with heat index readings
peaking around 100 to 105. Scattered storms possible through
the evening with torrential rainfall, gusty winds, and lightning
being the main threats.
* Another period of unsettled weather returns to the region by
late Wednesday and Thursday.
&&
.UPDATE...
Issued at 846 PM EDT Sat Jun 29 2024
Widely isolated showers and storms continue this evening across the
region. We may continue to see isolated activity pop up tonight into
early tomorrow morning as a weak front approaches from the north.
The convection thus far within our CWA has been relatively mild
likely due to marginal mid-level lapse rates and weak capping in the
850-700mb layer. Still can`t rule out an isolated stronger storm
overnight, but conditions will become less favorable for robust
convection the deeper we go into the night. Forecast remains on
track.
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 344 PM EDT Sat Jun 29 2024
Afternoon satellite imagery and observations reveal partly sunny
skies across the forecast area. Temperatures were in the upper 80s
to the lower 90s. Dewpoints continued to hold in the lower-mid 70s
resulting in heat indices in the upper 90s to the lower 100s
(generally 98-104). The area remains generally devoid of convection
with the exception of a line of shallow showers over across Garrard
and into Madison county. Other storms were located up to our north
along the I-70 corridor.
With temperatures in the upper 80s to the lower 90s and dewpoints in
the low-mid 70s, instability has ticked up across the region with
MLCAPE values surging into the 1500-2500 J/kg range, with slightly
larger values of SBCAPE locally. While instability is decent, low-
mid level lapse rates and deep layer shear remain rather marginal
and the best synoptic scale forcing is off to our northeast. For
the remainder of the afternoon, isolated-scattered storms could
develop over the region. Current thinking is that our northeastern
sections would have the highest chance of seeing convection. Temps
will top out in the upper 80s/lower 90s before cooling into the 80s
by evening. An MCV evident WV imagery coming into central IN may
spark a round of shower/storms this evening across the region. HRRR
has been trying to drum up some convection mainly over the
Bluegrass, but approaching MCV/wind shift over IL/MO may be enough
to kick up some storms this evening. For now will continue to keep
30/40% PoPs going. Main threats with any storm will be torrential
rainfall, gusty winds, and frequent lightning.
Surface cold front will continue to push southward overnight and
some additional convection may fire along that boundary. However,
most CAMs keep the most significant convection to our
west/southwest. Another warm night of temperatures is expected with
readings only dropping into the mid-upper 70s.
For Sunday, surface frontal boundary is forecast to drop through the
region. This will bring cooler and less humid conditions to the
area. We may see some scattered showers along the front in the
morning across the north and then a few showers/storms could
continue through the afternoon across the south as the boundary
continues toward the TN valley. Highs will only warm into the upper
70s/lower 80s across southern IN with lower 80s (80-85) across
Kentucky.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Issued at 344 PM EDT Sat Jun 29 2024
By Sunday night, the cold front will be south of the region. Surface
high pressure, centered over the Midwest, along with upper ridging
will quickly clear skies over the Lower Ohio Valley. Cold air
advection from northerly winds on the eastern side of the high will
help drop low temperatures into the low 50s (southern Indiana) to
the low 60s (southern Kentucky) which is 15-20 degrees cooler than
Saturday night`s lows. The continued CAA will help to limit highs on
Monday to the upper 70s to low 80s. The cold front followed by
northern winds will also help knock dew points down into the 50s
which will help make things feel much more comfortable throughout
southern Indiana and central Kentucky, but as the center of the
surface high gets pushed across the Great Lakes, return flow will
begin lifting temperatures back into the 90s by Tuesday. This will
also begin lifting dew points across the region as Gulf of Mexico
moisture begins to get funneled up the Mississippi and Ohio River
Valleys. Dew points in the 60s will return on Tuesday before the 70s
on Wednesday. Upper 80s to low 90s are expected to remain into the
weekend, and with the pressure gradient between the surface high on
the East Coast and the approaching cold front to our northwest
increasing, warm air advection and moisture transport will increase.
This will push highs into the mid 90s and dew points into the mid
70s which will result in heat indices in the 100-104 range over the
western half of the CWA. Currently, this looks to be be the hottest
day of the week.
By Wednesday night, an approaching cold front being pushed by an
upper trough will push the upper ridge out of the Great Lakes region
and through New England, leaving more zonal upper flow north of the
upper high over the South. This will likely cause the cold front to
flatten from west to east north of the high to the south. This will
likely place the front just north of the CWA. In an environment with
precipitable water values climbing over 2", shower and thunderstorm
chances will begin increasing before the front gets pushed south of
the region by Friday or Saturday.
&&
.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 700 PM EDT Sat Jun 29 2024
Very isolated shower/storm activity has developed ahead of a weak
cold front this evening but will likely avoid TAF sites through the
overnight hours. Should one of these showers/storms impact a TAF
site, expect briefly reduced cigs/vis and gusty winds.
The wind shift associated with the front will pass through the
region early tomorrow morning. Post-frontal northwest winds could
get gusty at times during the afternoon and near 20kts. In addition
to the winds, some low-end VFR to high end MVFR stratus may
accompany the front for several hours before clearing out tomorrow
afternoon from northwest to southeast.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...DM
SHORT TERM...MJ
LONG TERM...KDW
AVIATION...DM
Area Forecast Discussion
National Weather Service Tallahassee FL
852 PM EDT Sat Jun 29 2024
...New UPDATE...
...INSTANCES OF FLASH FLOODING FROM HEAVY RAIN ARE POSSIBLE THIS
EVENING IN PARTS OF SW GA DOWN TO THE FL STATE LINE...
.Correction...Added content to the Marine section
.UPDATE...
Issued at 843 PM EDT Sat Jun 29 2024
Clusters of slow-moving thunderstorms with embedded heavy rain
rates have been ongoing this evening across parts of SW GA just
east of the AL border down to northern Leon County. Instances of
flash flooding are possible with this activity over the next
couple hrs or so as these cells gradually track eastward. If you
are under a Flood Advisory of Flash Flood Warning, please avoid
any flooded roads, which are especially difficult to see at night.
Convection likely persists for the first half of tonight before
diminishing after midnight, per the latest HRRR run. Therefore,
the main changes to tonight`s forecast were increasing rain
chances where the axis of highest precipitation is currently in
place and added the explicit mention of "heavy rain" in our hourly
wx grids that coincide with definite PoPs of around 90% or more.
Hourly temperatures on the front end were adjusted as well to
account for the rain-cooled air mainly across the western half of
the Tri-State area.
&&
.NEAR TERM...
(Through Sunday)
Issued at 330 PM EDT Sat Jun 29 2024
Ridging aloft continues nudging in from the west through the
near term with a moist unstable airmass remaining in place over the
forecast area. Garden variety pop up storms are possible areawide
tomorrow with PoP`s generally maxing out in the 60-70% areawide.
PWAT`s ranging from 2.2-2.5" support efficient rainmakers, hinting
that a localized nuisance / flash flooding threat is possible with
these storms if they are slow moving and / or stall.
Heat remains a concern as well tomorrow, though there are some
caveats. Heat indices across our FL counties generally range from
108-112 with a few areas even reaching 113+, supportive of a heat
advisory. However, given the large coverage of storms tomorrow
during peak heating, rain cooled air with scattered anvil debris
from these storms may hinder most of the areas from realizing these
temperatures. Our SE AL and SW GA counties have heat indices > 108
as well, particularly in their counties bordering FL, though
uncertainty remains the same. Regardless, temperatures are expected
to once again be hot and muggy tomorrow afternoon. Make sure to wear
light clothes tomorrow, drink plenty of water, and limit time
outside if possible.
Tonights low temperatures are expected to drop to the mid to upper
70s with afternoon highs tomorrow reaching the mid 90s.
&&
.SHORT TERM...
(Sunday night through Monday night)
Issued at 330 PM EDT Sat Jun 29 2024
The short term period looks a bit unsettled with mid to upper level
ridging pushing over to the west and a weak front stalling out over
the area. How far south the front makes it is unclear at this point,
but it will likely create a local focus for shower and thunderstorm
activity With the most coverage expected Monday afternoon and
evening. A few strong storms will be possible along with isolated
pockets of heavy rainfall. Highs are forecast in the low to mid 90s,
however areas with the highest coverage of rain and clouds may end
up a few degrees below that. Lows are forecast in the mid 70s.
&&
.LONG TERM...
(Tuesday through Friday)
Issued at 330 PM EDT Sat Jun 29 2024
Ridging begins to build back overhead during the long term,
gradually lowering our rain chances through mid week. A few showers
and storms will still be possible, particularly along the seabreeze
in the afternoon, but widespread convection is not expected once the
ridge settles in. This will also allow temperatures to soar once
again, reaching the mid to upper 90s again by the end of the week.
Lows are forecast to remain fairly steady in the low to mid 70s.
&&
.AVIATION...
(00Z TAFS)
Issued at 703 PM EDT Sat Jun 29 2024
Shower and thunderstorm activity today will begin to diminish
after sunset with the remaining storms ending around 04Z-06Z.
During the overnight hours, winds will become light to calm. It is
possible for patchy fog to develop at our inland terminals but
confidence is too low to include in the TAFs.
Showers/thunderstorms may develop in the late morning into early
afternoon; however showers and thunderstorms are more likely
expected to return during the afternoon Sunday, hence VCTS at all
terminals, with higher confidence around 20z for TSRA at most
terminals.
&&
.MARINE...
Issued at 331 PM EDT Sat Jun 29 2024
Offshore buoys were reporting SW winds near 10 kts with 2-ft seas
and a dominant period of 4-5 seconds this evening.
From CWF Synopsis...Wave periods notably increase overnight via
southerly swells with an uptick in seas. Southwesterly flow around
10 knots and seas around 3 to 4 feet will prevail through most of
the weekend until a weak frontal boundary pushes into the Gulf and
winds become light and variable early next week. Wave heights of 3-4
feet will predominantly be attributed to the tropical disturbance in
the southern Gulf of Mexico that is currently crossing the Yucatan
Peninsula. Scattered showers and storms are expected through the
weekend and early next week with activity generally greatest in the
overnight and early morning hours as the diurnal land breeze
circulation is at its peak.
&&
.FIRE WEATHER...
Issued at 331 PM EDT Sat Jun 29 2024
Tomorrow, isolated storms are expected to occur across the
area in the afternoon hours with gusty and erratic storms near and
within them. This will continue over the next few days as a moist
and unstable airmass remains over the forecast area. Transport winds
over the next few days will be variable in direction ranging from
around 5-10mph with increasing mixing heights each afternoon. Fair
to generally good dispersions are expected areawide. At this time,
there are no fire weather concerns at this time.
&&
.HYDROLOGY...
Issued at 243 AM EDT Sat Jun 29 2024
Widespread forecast rainfall totals through the next 5 days are
generally expected to remain around 1-2 inches, with locally
higher totals possible. This is primarily due to deep tropical
moisture remaining in place over the region through the middle of
next week. There are currently no flooding concerns at this time;
however, localized flash flooding from training thunderstorms will
be possible, especially in poor drainage and urban environments
due to very efficient rain processes and high rainfall rates.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 77 93 76 93 / 80 70 40 70
Panama City 80 91 78 92 / 30 70 50 60
Dothan 76 93 75 95 / 60 70 30 50
Albany 76 94 75 95 / 60 70 30 60
Valdosta 76 94 76 94 / 60 70 30 60
Cross City 76 93 75 91 / 50 70 40 60
Apalachicola 80 91 78 88 / 30 70 50 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 8 AM EDT /7 AM CDT/ Sunday for
FLZ108-112-114.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...IG3
NEAR TERM...Worster
SHORT TERM...Merrifield
LONG TERM....Merrifield
AVIATION...Montgomery
MARINE...Merrifield
FIRE WEATHER...Worster
HYDROLOGY...Bunker
Area Forecast Discussion
National Weather Service Tucson AZ
128 PM MST Sat Jun 29 2024
.SYNOPSIS...Active monsoon pattern this weekend into early next
week bring daily chance of showers and thunderstorms. Some storms
will generate strong winds and locally heavy rainfall.
&&
.DISCUSSION...Latest visible satellite imagery early this afternoon
is still showing quite a bit of mid level clouds across most of
southeast Arizona as an MCV is pushing north from Santa Cruz/SW
Cochise County. This cloudiness has kept temperatures from warming
up as quickly as usual today and depending on how much persists into
the mid afternoon hours, may keep Tucson below 100 degrees today.
It`ll be a close call. Not much on radar at this time with just a
few light showers mainly east of Tucson. Given the placement of the
MCV and subsidence behind it as the MCV pushes north, convective
development is on the slow side today. Latest HRRR shows a few
storms mainly west of Tucson through the afternoon and this is where
more abundant solar insolation has occurred today. Elsewhere, a
continuation of some scattered shower activity with perhaps an
embedded thunderstorm or two that could produce brief heavy rain.
All in all, certainly a much quieter afternoon period than what we
experienced yesterday.
Heading into this evening and the overnight hours, our focus shifts
toward the disturbance currently seen on WV imagery over Chihuahua
that is pushing to the west-northwest. This will help trigger
convection across NE Sonora/NW Chihuahua early this evening that
will push to the northwest later in the evening and overnight hours.
The convection will be aided by the deep layer lift from the
aforementioned disturbance, along with outflow boundaries acting on
elevated CAPE. Don`t be surprised if you hear rumbles of thunder in
Tucson in the midnight to 3 am time frame. This area of convection
will also help reinforce the deep moisture over our area. Latest
HRRR/CAMs show convection winding down around or shortly after 12Z.
Sunday into Sunday night is shaping up to be a very active period.
Sunday morning cloud cover should diminish fairly quickly as 15 to
20 kt southeasterly flow aloft pushes clouds from the overnight
convection away and allows the atmosphere to reload. The combination
of increasing instability (MLCAPE at or above 1000 J/KG in many
locales), and another disturbance approaching aloft will set the
stage for widespread shower and thunderstorms Sunday afternoon into
evening. Most of the forecast area is at risk for these storms,
though the focus for the strongest storms and greatest flash flood
risk will be from western Cochise County to points westward
including Tucson Metro and into the Tohono O`oodham Nation. HREF 3
hour QPF 40km neighborhood probabilities exceed 70% for 1 inch or
and around 10% for 3 inches or more near the Tucson Metro. WPC has
the area referenced above already outlined in a slight risk for
excessive rainfall and that continues to look good. Greatest concern
for flash flooding will be due to storm mergers/clustering as
individual storm motion will be around 15 mph. Later shifts will
need to consider hoisting a Flash Flood Watch for portions of the
forecast area. There is also a threat for strong gusty outflow winds
Sunday afternoon into evening, especially from Tucson and point
north and westward where DCAPE values exceeding 1500 J/KG will
assist in the development of these strong outflows. HREF members are
all in agreement of this scenario with strong outflows pushing NW
across Pinal County which would result in areas of blowing dust.
This is also something we`ll be monitoring.
The disturbance that is expected to result in the widespread
convection Sunday will move to our north by Monday with the flow
aloft a bit more from the south to southwest. We`ll have to see just
how worked over the atmosphere is and how much subsidence there is
on Monday for less convective activity. Given the flow pattern, the
focus will tend to be on areas from Tucson eastward.
The active and moist pattern will continue into the middle of the
week and through July 4. However, it`s a little bit challenging to
discern the more active days/locations at this time. By Friday and
into next weekend as the high aloft reestablishes itself and
strengthens to our north, our flow pattern will be more from the
NE/ENE and this would be more favorable to bring storms in off the
Mogollon Rim/Gila Mtns, a pattern we have yet to see this monsoon.
&&
.AVIATION...Valid through 01/00Z.
SCT-BKN clouds at 8-12k ft AGL thru the fcst period. SCT-SHRA/-TSRA
with brief MVFR conds nr storms, most likely between 30/03Z and
30/11Z and then again aft 30/20Z. SFC winds 10 kts or less with the
occasional afternoon gusts, except stronger due to gusty outflows
from storms. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Relatively deep moisture will stick around through
the forecast period. This will bring scattered thunderstorms and
showers this afternoon and especially tonight with an uptick in
thunderstorms Sunday afternoon/evening. Next week will see daily
chances of afternoon and evening showers and thunderstorms. Strong
erratic gusty winds of 40 mph or higher can be expected with any
storm development, along with locally brief heavy rainfall. Outside
of thunderstorm winds, 20-foot winds will generally be 15 mph or
less each afternoon with the occasional gust of 20 mph. Min RHs will
generally be around 20% in the valleys and 30s in the mountains with
good overnight recoveries.
&&
.CLIMATE...The triple-digit high streak for Tucson, which
currently stands at 33 consecutive days, is at risk today thanks
to yesterdays two brief heavy rain events that hit the airport and
cloud cover.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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