Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/30/19
AREA FORECAST DISCUSSION
National Weather Service Albany NY
954 PM EDT Sat Jun 29 2019
.SYNOPSIS...
A cold front and potent upper level disturbance will bring
scattered showers and thunderstorms to the region late tonight
into Sunday along with cooler temperatures and breezy winds.
Some storm may produce small hail. Less humid and seasonably
warm conditions will return for Monday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Updated at 10 pm. Storms have weakened across northern NY and no
severe weather is expected from those showers as they work their
way south across the Adirondacks overnight. Showers may reach
the upper Hudson Valley and southern Green Mountains well after
midnight as a strong short wave digs southeast from southern
Quebec toward eastern NY and western New England. Farther south,
a mostly clear and warm night will continue with lows settling
into the 60s. Previous discussion is below.
Updated at 8 pm. Storms have moved out of the southeast part
of the forecast this evening. We are now watching an area of
showers and thunderstorms moving across far northern NY
associated with an unseasonably strong upper level trough
digging southeast from Quebec toward New England. A few warnings
have been issued on these storms for areas near the Canadian
border, however we do expect some weakening with the sunset
during the next couple of hours. Showers and thunderstorms will
become likely over the southern Adirondacks late this evening
through the overnight but we believe that the severe risk will
be minimal by the time they get into our forecast area.
Meanwhile, we are looking at a mostly clear, warm night for
areas from I-90 southward, with increasing clouds after midnight
from Albany northward. Previous discussion is below.
Marginal to Slight Risk for Severe Thunderstorms through sunset
today.
GOES16 water vapor imagery shows a weak trough sliding
southeastward through the mid-Atlantic with plenty of dry air in
its wake with a few shortwaves pushing to our south through PA.
Visible satellite combined with 20Z surface observations show a
wind shift boundary positioned inbetween ALB and POU
southwestward towards the Southern Tier. The air mass south of
this boundary shows is very moist with dew points in the mid to
upper 60s with SPC mesoanalysis showing SBCAPE values over
2000J/kg through the mid-Hudson Valley, Catskills into western
New England. While the thermodynamics are impressive, shear is
rather weak with effective shear values only 25-35kts in this
area. As this boundary pushes through the buoyant sector
positioned across our southern zones, it is sparking a few
thunderstorms but so far none have been impressive. This is
likely due to very weak mid-level lapse rates less than 6C/km
combined with weak forcing for ascent and limited storm residence
time within the buoyant sector. We will continue monitoring
storms through 23z as an isolated or two strong to severe storm
cannot be ruled out with gusty winds and large hail (mainly due
to high instability values) being the main hazards. We lowered
POPs from likely to chance through 23z in the latest update
across the southern half of the forecast area to reflect latest
thinking and the isolated to scattered storm coverage seen in
radar/satellite trends.
Once our wind shift boundary exits into southern New
England/NYC towards 23/00z, there should be a break for dry
weather as the dry air seen on GOES16 water vapor intrudes into
eastern NY and western New England in the wake of the boundary.
We thus gradually removed PoPs and decreased cloud coverage for
the evening hours. Since this boundary is not introducing any
real air mass change with winds only shifting from the southwest
to the west-northwest, we should remain warm and muggy through
the evening and overnight.
Tonight our compact and potent shortwave trough continues digging
southeast towards the US/Canadian border, leading to strong height
falls over the Adirondacks into the Upper Hudson Valley. Latest RAP
and high-res NAM show 500-1000J/kg SBCAPE lingering through 04z
Sunday thanks to the long June days coincident with strengthening 0-
6km shear vectors between 30 and 40kts. Therefore, included
potential for heavy rain and gusty winds from possible stronger
thunderstorms in the Adirondacks and parts of the Upper Hudson
Valley 00z to 04z Sunday. Coverage may be limited as the better
forcing should be still north of our region but still wanted to
include the potential for stronger storms this evening.
Otherwise, we confined the highest POPs for showers and
thunderstorms to areas well north and west of the Capital Region
overnight where the best heights falls will ensue before
gradually trending PoPs southward after 09z as our potent
shortwave trough slides into the North Country.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Very strong height falls and strong cyclonic vorticity advection
will push southeastward through eastern NY and western New
England on Sunday as an anomalous shortwave trough and its
associated upper level cold pool impacts the Northeast. The
shortwave`s 500 mb heights, as per the latest GEFS, are 2 to 3
standard deviations below normals which helps put the dynamics
of this shortwave into perspective. Its associated trough axis
should swing from north to south during the morning hours,
reaching the Adirondacks, Upper Hudson Valley and Lake
George/Saratoga region by 12z - 15z Sunday and pushing through
the Capital Region into western New England and the mid-Hudson
Valley from 15z to 18z. An initial area of showers and some
thunderstorms can be expected with the trough axis/surface cold
frontal passage with winds shifting from the west to the
northwest. Our region will then be under the influence of the
upper level cold pool from midday into the afternoon hours. With
500mb isotherms ranging -17C to -21C and WBZ heights under
10kft, we should see more convectively driven and scattered
shower and storm coverage. We continued to mention the potential
for small hail and gusty winds in any thunderstorms as well
given this set-up. The latest guidance continues to place the
steepest lapse rates of 6.5-7C/km east of the Hudson River into
western New England so these regions should see more numerous
shower/storm coverage. We also collaborated with SPC to expand
the marginal risk for severe weather into this area. Such an
environment also means any stronger updrafts can quickly lead to
cloud to ground lightning so those with outdoor events or
activities planned for Sunday should stay vigilant.
Besides scattered showers and storms increasing in coverage
underneath the cold pool tomorrow, winds should also turn breezy
in the afternoon in the wake of the trough axis. Areas that
receive more sunshine under the steep lapse rates should
experience better mixing with gusts up to 25 to 30mph possible.
Placed the highest gusts in the Catskills and Mohawk Valley
which should see less shower/storm coverage than areas directly
under the cold pool and thus better chance for some breaks of
sun.
Given how early in the day the trough axis passes through,
northerly flow and cold air advection should occur through most
of the day which will limit high temperatures to the mid to
upper 70s in valley locations and 60s for those at 1000ft or
higher. The Greens and northern Berkshires may end up being the
coolest ranging from the 60s to lower 70s given greater
storm/shower coverage and cloudier skies. The mid-Hudson Valley
and NW CT should see some morning sun ahead of the approaching
cold front so they have a better chance of nearing the 80 degree
mark.
Our shortwave trough should exit into New England by late
afternoon with strong subsidence and height rises following
quickly in its wake. We decreased POPs and cloud coverage
quickly after 21z from west to east to illustrate the drying
trend and clearing trend. Dew points will be falling through day
under the northerly flow so those looking for less humid and
cooler conditions can look forward to Sunday night. In fact,
clear skies should help temperatures fall into the 50s (even 40s
for the higher terrain).
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Guidance is in good agreement regarding the longwave pattern for
next week with a broad ridge across the CONUS with a low making
gradually eastward progress across Canada. A short wave is expected
to ride down the east side of the ridge bringing some showers to the
area Monday night possibly into Tuesday. Fair weather is then
expected through mid week as the ridge establishes itself over the
region. Our next chances for convection are expected Thursday the
4th as a dampening short wave approaches and passes over the region.
As we close out the week and heading into the weekend unsettled
weather is expected as a cold front approaches and sweeps through in
association with a short wave rotating about a large upper low as it
moves eastward across Hudson Bay to Newfoundland/Labrador.
Expecting seasonable temperatures to start July with highs in the
mid 70s to lower 80s. Warmer, above normal readings, are expected
for the remainder of the week with highs mainly in the 80s with some
90s possible as 850 mb temperatures to rise to near 20C, +1 to 2
standard deviations. In addition humidity levels are expected to
noticeably increase.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected at the TAF sites through this
evening. Showers over the Adirondacks may get as far south as
GFL after 06z with brief periods of MVFR conditions possible. A
period of showers is likely at GFL and ALB Sunday morning, then
scattered showers and thunderstorms can be expected at all of
the TAF sites during the afternoon as a strong upper level
system tracks from Quebec toward New England. Conditions through
the day Sunday will be mainly VFR, except for briefly MVFR in
scattered showers. The heaviest showers Sunday may contain a
brief period of hail or gusty winds along with lightning.
Winds will be light and variable tonight shifting to west-
northwest at around 10 kts on Sunday with gusts of 15 to 20 kts
during the afternoon.
Outlook...
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.
Monday Night: Moderate Operational Impact. Chance of SHRA.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Independence Day: Moderate Operational Impact. Chance of SHRA...TSRA.
&&
.FIRE WEATHER...
Wind gusts up to 25 - 30 mph possible on Sunday...
A strong upper level disturbance will bring isolated showers
and thunderstorms to the region tonight before more widespread
showers/storms arrive Sunday. RH values will range from 55 to 75
Sunday afternoon before turning lower on Monday, ranging from
45 to 55 percent. RH values both tonight and Sunday night should
range 85 to 100 percent.
Strong winds are expected on Sunday with westerly winds shifting
to the north-northwest during the day and becoming sustained
between 10 and 15mph with gusts up to 25-30mph possible.
Northwest winds should weaken after sunset ranging 5 to 12mph
through midnight before decreasing further by sunrise.
Winds will be stronger and variable in direction in and near
any thunderstorms.
&&
.HYDROLOGY...
Showers and thunderstorms and thunderstorms will drop southward
across the Adirondacks tonight but rainfall should not be heavy
enough to cause any signifcant flooding. Farther south, expect
a dry warm night tonight.
More widespread coverage of showers and thunderstorms are
expected Sunday with locally heavy downpours possible but again,
any flooding should be reserved to brief urban/poor drainage
flooding. Areas east of the Hudson River into western New
England should see the most shower/storm coverage.
Drier weather is expected Monday before chances for showers
return Monday night.
Please visit our Advanced Hydrologic Prediction Service /AHPS/
web page for specific area rivers and lakes observations and
forecasts.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Speciale
NEAR TERM...MSE/Speciale
SHORT TERM...Speciale
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...Speciale
HYDROLOGY...Speciale
Area Forecast Discussion
National Weather Service La Crosse WI
648 PM CDT Sat Jun 29 2019
.SHORT TERM...(This evening through Sunday)
Issued at 248 PM CDT Sat Jun 29 2019
Several concerns with how the convective trends are going to play
out through Sunday leading to a low confidence forecast in the near
term. Still watching the remains of the overnight convective complex
over northwest Minnesota that none of the hi-res meso-scale models
handled well and all would suggest should no longer be occurring.
The RAP has been consistent taking the MCV from this complex
southeast across northern and eastern Wisconsin overnight and if
this complex can survive through the afternoon, it could ride along
the edge of the MU CAPE gradient and come across the area north of
Interstate 94. However, there has been a recent decrease in the
lightning and some cloud top warming, so confidence in the complex
making into the area is very low.
Another complex, or two, should develop over North Dakota and then
ride along the edge of the upper level ridge axis/CAPE gradient
overnight. All the meso-scale models show this scenario, but have
much different evolutions and timing. Some would bring the remains
of a complex into the area before daybreak while others hold off
until almost mid-morning. Most of the models would suggest the
complex would mainly be over Wisconsin, but again, others bring it
across the entire area. For now, have trended toward some activity
coming in around daybreak or a bit later and moving across mainly
Wisconsin.
This complex also lends some doubt to how warm it will get Sunday.
The heating will be delayed from the clouds and potential rain in
the morning. However, subsidence behind the complex should allow for
some clearing to occur during the peak heating and highs in the
lower 90s still could be reached. With dew points well into the 70s,
heat indices around 100 possible southwest of Interstate 94. It
still may be necessary to issue a heat advisory for Sunday.
Another round of convection will be possible late Sunday afternoon
as a cold front moves across Minnesota. Abundant energy will be
available ahead of the front with ML CAPE values of 4000 J/Kg shown
by the RAP. Some capping will be in place ahead of the front but
forecast sounding show this could be eroded by late afternoon. The
shear does not look overly strong with 30 to 35 knots in the 0-3 km
layer. Enough to support a risk for some severe storms with damaging
winds being the main threat.
.LONG TERM...(Sunday night through Saturday)
Issued at 248 PM CDT Sat Jun 29 2019
On Sunday night, a cold front will move south into the region. The
airmass will remain very unstable into the evening with ML CAPES
of 4000 to 4500 J/kg. With 0-3 km shear up to 40 knots, the main
threat will be damaging winds and maybe large hail. The main
question is with a strong cap over the region how widespread the
showers and storms will become and how far south will they get.
The meso models currently suggest that convection will be either
be ongoing or developing somewhere near the Interstate 90
corridor by early evening. However, this may change depending on
where the boundary lays out on Sunday morning. With precipitable
water values around 2 inches and warm cloud depths of 4-4.5 km, any
showers and storms will very efficient rain makers. May need a
Flash Flood Watch in areas where storms train.
This front then looks to linger across the area through the work
week. As waves move along this front, there will be periodic
showers and storms. There is much uncertainty on the location and
timing of these showers and storms. Afternoon and evening ML CAPES
are in the 1500 to 3000 J/kg. The 0-3 km and 0-6 km shear appears
to be weak for much of the weak. However, at times, they do
increase as waves move through the region. During these times,
there will be potential for severe storms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 648 PM CDT Sat Jun 29 2019
Main aviation concerns are on the potential for Thunderstorms at
the TAF sites Sunday morning with higher chances Sunday afternoon
into Sunday evening. Thunderstorms will approach the region from
the northwest late tonight into Sunday morning. However a strong
CAP in place may keep this activity north of the TAF sites. A cold
front slides in from the north by Sunday afternoon and we will
likely see thunderstorms develop along the front and move south
into the TAF sites, mainly after 21Z. Threats from the storms will
include, damaging winds, large hail, heavy rain, and frequent
lightning.
&&
.HYDROLOGY...Sunday into Sunday night
Issued at 648 PM CDT Sat Jun 29 2019
Precipitable water values of 2 inches and warm cloud depth of 4 to
4.5 km will set the stage for a heavy rain environment on Sunday.
The first round of thunderstorms Sunday morning look to track
north of Interstate 94, and will likely be weakening as they move
into a cap. We should then see thunderstorms develop Sunday
afternoon along an approaching frontal boundary. The storms will
be capable of producing heavy rainfall and could be rather slow
moving. Additional rounds of storms are possible Sunday evening
into Sunday night. The high rainfall rates, and the potential for
repeated rounds of storm raises the concern for flash flooding.
850 mb moisture transport becomes oriented parallel to the front
Sunday evening so this could limit the heavy rain threat. However,
with recent rains, soils are saturated in some areas and there
are a few rivers already elevated or in flood. Will be issuing an
ESF (Hydrologic Outlook) to cover the potential flooding threat
and if confidence increases, a flash flood watch may be needed for
Sunday afternoon into Sunday night.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...04
LONG TERM...Boyne
AVIATION...Wetenkamp
HYDROLOGY...Wetenkamp
Area Forecast Discussion
National Weather Service Bismarck ND
938 PM CDT Sat Jun 29 2019
.UPDATE...
Issued at 938 PM CDT Sat Jun 29 2019
Trimmed the western four counties (Dunn, Stark, Hettinger and
Adams) from the Tornado Watch. Several warnings issued earlier for
cells in Stark and Morton counties, but most recent cell has
weakened significantly as it moved through eastern Morton.
Although quiet at the time, continuing to monitor southeastern
parts of our area. Also adjusted pops to based on latest trends,
mainly lowering pops.
UPDATE Issued at 702 PM CDT Sat Jun 29 2019
Update to end the heat advisory. The impressive
easterly/northeasterly outflow from the morning thunderstorms pretty
much dominated the afternoon clouds, wind, temperature, and even
dewpoint fields that were forecast. We had thought that the higher
temps would eventually be realized by mid afternoon...but the
temperature/humidity combination to make the heat index never came
to fruition.
UPDATE Issued at 610 PM CDT Sat Jun 29 2019
Update for tornado watch # 463 for parts of southwest and all of
south central ND...mainly from Dunn/Adams counties eastward to
Foster/Dickey counties...including Dickinson, Hettinger, Mandan,
Bismarck, Fort Yates, Carrington, Jamestown, Oakes.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 331 PM CDT Sat Jun 29 2019
Main forecast issues this afternoon and tonight will be
thunderstorms and heat.
The easterly winds and resultant cooler air from outflow from
earlier thunderstorms has kept variable cloud cover over central
North Dakota. Will take Stutsman County out of the heat advisory
because of this.
Because of the outflow from earlier storms, and latest mesoscale
analysis from SPC indicates that even at 2 pm CDT there is still
some CIN that is still squelching the potential surface-based cape
of 2500-5000 J/kg. However, the potential is still there with MU
CAPE above the mixed layer of 3000-5000 J/kg. Low level jet still
remains in place, with the northern edge of the LLJ and surface warm
front now in southern Manitoba. The surface cold front has been slow
to enter western ND today, but extended from near Williston to just
east of Beach and Bowman.
Despite the cooler air moving in, the latest RAP sounding for
Jamestown indicates a return of warmer air (90F) by around 00z, and
increases low level southeasterly flow. The current mesoanalysis
from Bismarck to Jamestown indicates an effective significant
tornado parameter of 4-9. Bulk shear is perpendicular to the north-
south cold front, so expect discrete cells to develop. Needless to
say, plenty of available CAPE energy just above the surface, with
higher dewpoints aloft as well with the LLJ, and plenty of effective
shear remain. Large hail and damaging winds will be the main threat,
as well as isolated tornadoes. Upper level impulses moving
northeastward in the southwest flow aloft, along with convergence
along the surface cold front advancing eastward into central ND will
be the kicker for thunderstorms. Even now at mid-afternoon, upper
level impulses are kicking off thunderstorms in northeast
Montana/northwest ND/southeast Saskatchewan behind the cold front.
Expect things to quiet down from west to east late tonight. Cooler
and noticeably drier on Sunday with dewpoints in the 50s returning
to our area.
.LONG TERM...(Sunday night through Saturday)
Issued at 331 PM CDT Sat Jun 29 2019
We return to more of a quasi-zonal flow through the remainder of
the long term period. So not quite the heat and humidity, but the
threat of thunderstorms will remain daily/nightly in the forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 702 PM CDT Sat Jun 29 2019
Thunderstorms are expected to develop over parts of central and
western North Dakota - with best chances at KDIK until around
03z...at KBIS and KMOT until around 05z...and at KJMS until around
07z. Severe storms are possible with large hail, damaging winds,
lightning, and possible tornadoes through 06z, especially at KDIK,
KBIS, and KJMS.
The cold front at 00z extended from east of Stanley to just east of
KDIK to east of KHEI. The cold front will push east this evening,
reaching KJMS by 05z-07z. Southeast winds ahead of the front and
northwest winds behind it. VFR conditions later tonight and
all day Sunday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JNS
SHORT TERM...JV
LONG TERM...JV
AVIATION...JV
Area Forecast Discussion
National Weather Service Quad Cities IA IL
644 PM CDT Sat Jun 29 2019
...00z AVIATION UPDATE...
.SYNOPSIS...
Issued at 329 PM CDT Sat Jun 29 2019
At 230 PM a hot and humid airmass is in place across eastern Iowa,
northeast Missouri, and parts of northwest Illinois. Dew points
ranged from the upper 60s in Freeport to the upper 70s at Fort
Madison, Keokuk, and Fairfield. This was producing heat indices of 99
to 105 in south of a line from KMXO to KCWI to KVYS. A frontal
boundary stretched from Waterloo to Monticello to Clinton to KVYS.
Scattered showers and storms were beginning to develop along a
Davenport to Princeton Illinois line.
&&
.SHORT TERM...(This Evening through Sunday)
ISSUED AT 329 PM CDT Sat Jun 29 2019
My main forecast concerns are temperatures and chances of
precipitation. Models are in good overall agreement but big
differences between the synoptic and convective allowing models over
the next 24 hours.
Isolated showers and thunderstorms are possible late this
afternoon into this evening with convergence along a pseudo frontal
boundary across the region. There is a 10 degree dewpoint drop
across the front. This may help to focus thunderstorm development
late this afternoon. Risk of showers and thunderstorms will fall once
the temperatures begin to cool. The HRRR shows convection
lingering in this area between 2 and 3 UTC. Shear is weak and
showers and storms will slowly drift across the area.
Our focus then shifts to tonight. Synoptic models show a temperature
and dewpoint gradient across the region they may lead to a Mesocale
Convective System (MCS) tracking across the area Sunday morning. The
850 MCS track can be highlight by the 18 to 20C temperatures at this
level which several synoptic models show across the area. This is
also in the same area where models depict a strong CAPE gradient
which in the MCS may want to ride However the 200mb divergence is
farther to our north and east across Minnesota and Wisconsin which
would say the better convection and storms would be to our northeast
Sunday morning. The 4km NAM Nest develop an MCS tonight across
Minnesota and depict it moving into our area Sunday morning but the
HRRR on develops scattered convection overnight. The risk is then
there for showers and storms Sunday morning and afternoon.
The MCS potential has a huge impact on the forecast for temperatures
and heat indices on Sunday. If an MCS develops and moves across our
area that will limit warmer temperatures until later in the day . if
there is no lingering thicker cloud cover from it. The current
forecast has temperatures in the lower 90s with heat indices
maximizing near 100 or 101. Both solutions are possible and for this
reason there is not a heat advisory for Sunday. We will revisit
this with later shifts.
.LONG TERM...(Sunday Night through next Saturday)
ISSUED AT 329 PM CDT Sat Jun 29 2019
Sunday night...In the wake of whatever convective system can make it
down acrs the area earlier on Sunday, thermal ridge acrs the plains
over to the GRT LKS will look to get dampened acrs the Dakotas and
MN by passing ridge-riding short wave. The next round of MCS
generation parameters come together acrs SD, the southern third of MN
and into WI for renewed development of convective clusters Sunday
evening. Of course being this close, some chance for a portion of
this activity to bleed down into the northern or northeastern CWA
late Sunday night into Monday morning. It will be battling the
ongoing elevated mixed layer as it does and have trouble
maintaining, or it could develop a cool pool with it`s own shear
mechanics and move down into portions of the local CWA as a strong
to severe storm complex with winds and heavy rain. This may be the
same scenario for days to come living on the edge of the "ring-of-
fire" pattern.
Monday...As with many days in the bulk of the longer range period,
much will depend on how much or if any of the CWA get`s impacted by
a nocturnal MCS or storm clusters from the north, and then the
associated lingering debris affecting how warm our area gets. With a
lack of debris and enough daytime recovery, much of the area may
near heat headline criteria again Monday afternoon. Then there will
be again a nocturnal chance for storms especially in the north later
Monday night into Tue morning. Enough high to extreme instability to
the south for ringing storms on the edge of the heat dome to produce
strong to damaging winds even with marginal shear profiles.
Tuesday through next Saturday...Tuesday may be similar to Monday
being hot and humid with nighttime storm chances, before signs of the
continued ridge dampening may bring the storm track further south
for a more direct line acrs the local area Wed into Friday. Rounds
of moderate to heavy rainfall may start to add up acrs portions of
the area mid to late week with some local river implications
possible. Longer range signs suggest that maybe high pressure
building south down acrs the Upper MS RVR Valley and GRT LKS may
shunt the storm track or convective action zone to the south of the
region from KS over to the OH RVR Valley from late Friday and
through the next weekend. The pattern shift to bring about cooler
temps as well. or at least to more seasonable levels later in this
period. ..12..
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 635 PM CDT Sat Jun 29 2019
Widely scattered convection will continue through sunset before
diminishing. CID and MLI would appear to be most susceptible
and will continue to monitor radar trends and amend if needed.
Some CAM guidance is suggesting potential for storms that form
over the Dakotas tonight could move into the area tomorrow
morning, while other guidance keeps this activity north. This
uncertainty owes to low confidence and therefore have kept out any
mention for now. Expect MVFR to IFR conditions in any convection,
with VFR conditions generally otherwise. There is a chance of some
patchy fog late tonight at MLI, which received some rain earlier.
&&
.HYDROLOGY...
Issued at 1215 PM CDT Sat Jun 29 2019
It still appears that an active weather pattern with an ongoing
storm track acrs portions of the upper Midwest will last through the
upcoming week. Latest indications suggest that the resultant rounds
of heavy rain will most likley occur acrs areas to the north over
southern MN, northern IA and WI. Some recent heavy rainfall has
already fallen acrs portions of these areas during the past few
days. This and additional rounds of rain will run-off and eventually
make it into the upper basin of the Mississippi River system and
flow southward. This will most likely produce eventual rises on the
local stretch of the Mississippi during this coming first week of
July. Currently most sites on the MS RVR are falling with Gladstone
LD18 dropping below the flood stage today, and only two other sites
remaining above flood stage. The exception is Dubuque down to
Bellevue areas which are showing steady to slow rises already from
recent rains upstream. This flow will continue to work on down and
continue to produce rises at the other sites through the upcoming
week. But with the recent downtrends along much of the local
stretch of the Mississippi, most rises are projected to remain
nominal and below the action stage. The exceptions may be at some of
the southern sites that are still high such as Keithsburg, Gladstone
LD18, Burlington, and Gregory Landing which are prevented from
falling below the action stage from the additional flow routed
through those sites. Some chance that Gladstone, Burlington and
Gregory Landing may approach the flood stage again by late next
weekend.
Some of the tributary rivers with reaches further to the north will
experience rises into next week as well from recent and projected
heavy rainfall in those areas. Rivers such as the Cedar, Iowa, and
Wapsi will experience rising trends, with a few sites making over
the action stage or held up above action if already over that stage.
The Wapsi at De Witt may rise to just under the flood stage by the
4th of July.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Heat Advisory until 9 PM CDT this evening for Benton-Buchanan-
Cedar-Clinton-Delaware-Des Moines-Henry IA-Iowa-Jefferson-
Johnson-Jones-Keokuk-Lee-Linn-Louisa-Muscatine-Scott-Van
Buren-Washington.
IL...Heat Advisory until 9 PM CDT this evening for Bureau-Hancock-
Henderson-Henry IL-McDonough-Mercer-Putnam-Rock Island-
Warren-Whiteside.
MO...Heat Advisory until 9 PM CDT this evening for Clark-Scotland.
&&
$$
SYNOPSIS...Cousins
SHORT TERM...Cousins
LONG TERM...12
AVIATION...McClure
HYDROLOGY...12
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
659 PM CDT Sat Jun 29 2019
.AVIATION... /00Z TAFS/
Rapid refresh models depict the East TX convective activity beneath
the shear axis aloft to enter into Central TX close to midnight. This
matches up well with the latest radar trends showing echoes moving
mainly south with outflow boundaries pushing west to trigger new
convection. Winds could become gusty briefly with the leading edge,
but the overnight timing should allow for the low level air to cool
enough to limit the potential for strong wind gusts. The shear axis
will still be rooted in East TX so it is unlikely the convection will
remain deep as the instability propagates into the San Antonio area.
Whats left for the forecast is a long period of vcsh as the skies
should be chaotic and tropical in nature with cirrostratus probably
being the most common cig. There could be brief mvfr episodes
overnight into early Sunday but expecting high moisture content in
the atmosphere to keep the air well mixed. Sometime in the midday
hours Sunday, future TAF updates will need to consider periods of
prevailing thunder as the shear axis becomes almost directly
overhead.
&&
.PREV DISCUSSION... /ISSUED 258 PM CDT Sat Jun 29 2019/
SHORT TERM (Tonight through Sunday Night)...
Across the U.S. this afternoon we see a trough over the Pacific NW,
upper ridging over the central Plains into the desert SW and an
inverted trof over far east Texas. The trof over the eastern part of
the state will be our main weather maker over the next several days,
lingering into next week. The overall pattern will be unsettled over
texas through much of the forecast so most periods will have mention
of pop except for mainly the far west along the Rio Grande where most
of the week will remain dry and rain free.
The upper level low pressure area that has been moving west over the
past few days has come into eastern Texas. Showers and storms are
ongoing over the Houston area, extending north into east Texas.
The latest runs of the HRRR and TXTech WRF show convection to the N
and NE making its way into our northern counties by evening. I think
we will have only minimal convection this afternoon, if any at all,
as visible shows very weak cu formation. Have scaled back pops the
rest of the day, but left them in over the far E and NE zones. Storms
could approach this area by 00z and linger through the evening. The
High resolution models take this activity and bring it through our
northern CWA late this evening into overnight so have kept decent POP
and scattered activity mentioned. We remain in the Marginal Risk
from SPC...with mainly wind being the biggest threat. Temps will be
fairly mild overnight. The upper low will be over the area on Sunday,
with scattered convection possible anytime of day, morning and
afternoon. Boundary driven storms and complexes could bring some
isolated rain totals well over 1 inch but confidence is low on timing
and exact location. Will likely be more clouds than sun on Sunday
so look for afternoon temps mainly in the mid to upper 80s. If the
storms come in early and leave some June sunshine...temp forecast
will bust...cant rule out some lower 90s for this reason. Will keep
a 30 pop ongoing through the eastern 2/3rds of the cwa Sunday Night.
The west will remain mostly dry.
LONG TERM (Monday through Saturday)...
The overall pattern really doesnt change much for most of next week.
The upper trof/low will linger over the state, get stretched a bit
north to south and eventually moves NE and weakens. So best rain
chances will remain the first half of the week with a moist
atmosphere and lack of high pressure ridging. Scattered pops will be
the result. As the influence of the upper low lessens by the 4th and
then Friday, rain chances finally go down, clouds decrease, and temps
near normal make a return. Low pressure over the Rockies mid week
will also bring back a stronger southerly wind for us...so look for
wind speeds to increase by mid week as well.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 71 87 70 88 71 / 50 50 30 30 10
Austin Bergstrom Intl Airport 70 86 70 88 70 / 50 50 30 30 10
New Braunfels Muni Airport 69 87 70 88 69 / 40 50 30 30 10
Burnet Muni Airport 70 87 68 87 68 / 40 50 30 30 10
Del Rio Intl Airport 72 93 72 93 72 / 10 10 10 - 10
Georgetown Muni Airport 70 87 69 88 69 / 50 50 30 30 10
Hondo Muni Airport 71 89 70 92 71 / 30 40 30 10 10
San Marcos Muni Airport 69 87 70 89 69 / 40 50 30 30 10
La Grange - Fayette Regional 72 87 71 89 71 / 50 50 20 30 10
San Antonio Intl Airport 71 88 71 89 71 / 30 50 30 10 10
Stinson Muni Airport 72 88 72 90 71 / 30 40 30 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation...Oaks
Short-Term/Long-Term...04
Public Service/Data Collection...33
Area Forecast Discussion
National Weather Service Fort Worth TX
740 PM CDT Sat Jun 29 2019
.AVIATION...
/00Z TAFs/
Thunderstorms currently rolling through the Metroplex have become
loosely organized along an outflow boundary arced in the shape
of a half-circle between the Dallas area and Waco. Storms will
continue to push southwest; exiting the DFW area while entering
the Waco area in the next hour. Gusty winds will be the primary
concern, though with dwindling surface heating, the severe threat
should be on its way down.
Easterly winds behind the outflow boundary should weaken later
this evening and eventually turn to the southeast by sunrise
Sunday. There is an outside chance of MVFR in the Dallas area
early Sunday, so will maintain the TEMPO group for DFW and DAL
for Sunday morning. For Sunday afternoon, there is an outside
chance for a few storms, but activity will have shifted mainly
south and west of the region along with the upper level
disturbance responsible for this evening`s convection.
30
&&
.SHORT TERM... /Issued 228 PM CDT Sat Jun 29 2019/
/Through Sunday Morning/
The main challenge in the short term forecast period will be
convective chances across the area.
Surface analysis this afternoon revealed an outflow boundary was
noted near a Bonham to Greenville to Nacogdoches line. This
feature...coupled with a diffuse mid/upper level impulse will
likely be the impetus for what should be a proliferation of shower
and thunderstorm activity. Mesoanalysis indicates a very healthy
instability profile with CAPE values in excess of 3500 J/kg.
Recent AMDAR data out of Dallas Love Field indicates respectable
north to northeasterly mid and upper level flow for late June and
as a result...we could see some loosely organized convective
modes that will generally travel from the northeast to southwest.
Given the inverted-V type sounding profiles and 0-3km theta-e
deficits of around 30K...we will have to contend with a damaging
wind risk. Deep layer shear around 30 knots will support quasi-
steady state updrafts and when coupled with the high to extreme
instability will yield a large hail risk. Heavy rain and flooding
will remain a threat, though storm motions should be sufficiently
high to preclude a long duration heavy rain episode. Any training
echoes, however, will be monitored for a brief flash flood risk.
The 12 UTC NAM NEST appears a little too aggressive with its
depiction of a well organized MCS by early evening. While I do
feel that the potential exists for a a loose complex of storms, it
still remains uncertain how expansive it will be. The current
forecast continues to favor scenarios advertised by the latest
HRRR and 12 UTC TTU WRF.
The best potential for rain/storms will be near and east of a
Killeen to Hillsboro to D/FW to Sherman/Denison line trough the
evening hours (though rain/storm chances exist west of this line).
Some nocturnal convection may persist tonight into Central Texas
and I`ll hold onto a 40-50 PoP near and south of the I-14/US HWY
190 corridor through 12 UTC. If a well established MCS gets going,
PoPs may need to be increased. There will be a potential for some
morning stratus/fog north of I-20 and east of I-35, but confidence
is a little too low to include in the forecast at this time.
Bain
&&
.LONG TERM... /Issued 228 PM CDT Sat Jun 29 2019/
/Sunday Through This Week/
We`ll continue to track out southwest-moving mid level
disturbance across Southeast Texas into South-Central Texas during
the day Sunday. Early in the day, expect most concentration of
showers/ thunderstorms to be in close in vicinity of this
immediate track with our far southern Texas counties seeing the
best chances through early afternoon. Afterward, surface
boundaries, differential heating, and pockets of instability along
the edge of anvil debris has me introducing 20% PoP through the
remainder of our CWA and to the Red River Valley. Though a strong
storm can`t be ruled out farther north where better instability
will likely reside from stronger insolation, Theta-E deficits in
the surface to 700mb layer do not look near as pronounced as
today, so the severe risk will be much less. High temperatures
remain problematic and completely at the mercy of who breaks out
of the clouds and who doesn`t. Central Texas areas may be hard-
pressed to get into the mid 80s, while lower 90s are likely in the
far northwest where more insolation is likely to be found Sunday
afternoon. Low convective chances will remain Sunday night, mainly
across Western Central Texas in vicinity of our system and better
ascent, which will slowly pull away from our area on Monday.
I can`t rule out isolated, more "airmass" type diurnal activity
across the region on Monday, but for most folks the forecast will
be seasonably very warm and humid with no additional rainfall. The
lull in precipitation chances will continue Monday night into
Tuesday morning, before increasing across Central Texas later
Tuesday and Tuesday night, as a shortwave lifts northward from the
Western Gulf of Mexico and across the Sabine River Valley.
Embedded shortwave energy will continue within a "weakness"
between two weak upper ridge axes moving into the mid week and 4th
of July holiday period with mostly diurnally-driven shower and
thunderstorm chances will continue across much of the area. I`ll
stress with weak flow and subtle forcing aloft and no synoptic
surface focusing mechanisms around, that this will NOT be a
complete washout for outdoor activities and fireworks, as the loss
of heating each evening should help diminish coverage and
intensity of most convective activity after dark. Otherwise, a
broad, but not overly intense subtropical upper high expands
across the Southern CONUS for more typical Summer conditions next
weekend and beyond. A few diurnal hit n` miss storms each
afternoon and early evening, but nothing widespread. Highs will
average in the lower- mid 90s.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 72 89 71 90 72 / 30 20 20 20 5
Waco 70 87 70 89 69 / 50 30 30 20 10
Paris 69 87 69 88 70 / 30 20 20 20 5
Denton 71 89 70 90 71 / 20 20 20 20 5
McKinney 71 87 70 89 71 / 30 20 20 20 5
Dallas 73 90 72 90 72 / 30 20 20 20 5
Terrell 71 87 70 90 71 / 30 20 20 20 5
Corsicana 69 86 68 86 69 / 50 20 20 20 10
Temple 70 86 69 88 68 / 60 40 30 20 10
Mineral Wells 69 90 68 89 68 / 20 20 20 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
30/11
Area Forecast Discussion
National Weather Service Green Bay WI
700 PM CDT Sat Jun 29 2019
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Sunday
Issued at 236 PM CDT Sat Jun 29 2019
The latest RAP analysis and satellite/radar imagery show a weak area
of high pressure stretching from northwest Ontario and across the
western Great Lakes early this afternoon. Low pressure resides over
the western Dakotas, with an associated warm front extending
southeast into southern Minnesota, and northern Iowa/Illinois.
Residual low level moisture and daytime instability contributed to a
cu field over central to northeast Wisconsin, while dewpoints mixed
out into the upper 40s over Vilas county. Meanwhile, north of the
warm front, a severe MCS is ongoing near the ND/MN border. As the
warm front returns northeast into northeast WI late tonight into
Sunday, forecast concerns mainly revolve around the potential for
severe thunderstorms.
Tonight...Fair weather cumulus clouds will dissipate early this
evening, but should see an influx of cirrus from the west from the
thunderstorm activity upstream. This should result in a mostly clear
to partly cloudy evening. Additional mcs activity is forecast to
develop over eastern North Dakota and northern Minnesota this
evening, then track towards northwest WI by late in the night. If
track and timing go according to plan, then should see increasing
clouds overnight with storms approaching north-central WI by around
6 am. Lows tonight ranging from the middle 50s near the U.P. border
to the middle 60s over the southern Fox Valley.
Sunday...A thunderstorm complex is expected to track southeast along
the warm front Sunday morning along the edge of the mid-level cap
and across northwest and central WI. Track of this complex diverges
in the higher resolution models by this time, but potential remains
for strong to severe thunderstorm activity to impact central WI in
the morning, where SPC has a slight risk. The main threat should be
damaging winds and heavy rainfall, but if there is a later arrival,
the storms could have a brief opportunity to interact with daytime
instability of 2000 j/kg of cape. The latest guidance suggest that
the threat of storms should end by around midday. Some concern that
storms may redevelop in the afternoon along the warm front. But the
atmosphere will need time to recover after the morning storms, and
will have to overcome mid-level capping. Chances will therefore
remain low. Some clearing is likely in the afternoon, which will
help temps warm into the mid to upper 80s away from Lake Michigan.
.LONG TERM...Sunday Night Through Saturday
Issued at 236 PM CDT Sat Jun 29 2019
Precipitation trends and the potential for severe thunderstorms
and heavy rainfall will be the main forecast concerns.
Models suggest that convection will be focused in central WI
Sunday evening, where low-level moisture convergence will occur
north of a warm frontal boundary. PWATs are forecast to approach 2
inches in our southwest counties, so heavy rainfall will be a
significant threat. CAPE is also expected to be in the 2000-3000
j/kg range during the evening, which will also support a severe
threat, even though deep layer shear is fairly weak (20-25 kts).
In the far north, a weak cold front may also trigger some storms
Sunday night. Have focused likely pops in those two areas, with
chance pops elsewhere.
The weak cold front is expected to sag through the area on Monday,
then lift back to the north as a warm front as low pressure
tracks toward the forecast area late Monday night into Tuesday.
The threat of heavy rainfall and severe weather should return as
the low pressure system and warm front approach. Will carry likely
POPs across part of the area Late Monday night into Tuesday,
though the placement of the highest POPs and QPF may need to be
adjusted as details come into focus.
After the low shifts east, the front is expected to drop south of
the region again Tuesday night into Wednesday night. This may
result in a bit of a lull in the precipitation, though confidence
is too low to go with a dry forecast.
The front should return as a warm front again on Thursday,
followed by a cold frontal passage Thursday night into Friday.
Precipitation chances should again be maximized near these
boundaries.
Medium range models suggest that Canadian high pressure may drop
into the western Great Lakes for the weekend, resulting in cooler,
drier and less humid conditions.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 659 PM CDT Sat Jun 29 2019
Generally VFR conditions through about 12 UTC Sunday with mainly
remnant cirrus debris moving overhead this evening from
dissipating convection earlier in the day over Minnesota.
Attention will continue to focus on when and where upstream
convection will fire over the Dakotas later this evening. How this
convection evolves will determine daytime flying conditions over
the forecast area on Sunday. Model guidance continues to be quite
variable on location and movement of thunderstorm complex forecast
to develop west of the Mississippi River overnight and track
somewhere over the western Great Lakes by mid-morning Sunday.
Latest model guidance appears to be slower in bringing
thunderstorm complex into western portion of the forecast area
Sunday morning.
Bottom line is that forecast confidence on evolution of thunderstorm
activity after 12 UTC Sunday is low, thus was more conservative
on explicit mention of thunder in 00Z TAFs. Once convection
develops over the Dakotas later this evening, will hopefully be
able to add more specifics to location and timing to thunderstorm
potential for upcoming 06Z TAF issuance.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......ESB
Area Forecast Discussion
National Weather Service Marquette MI
630 PM EDT Sat Jun 29 2019
.SHORT TERM...(This evening through Sunday)
Issued at 411 PM EDT SAT JUN 29 2019
WV imagery and RAP analysis indicated a mid/upper level ridge from
the Central Plains to Hudson Bay and a low just southeast of James
Bay resulting in nw flow through the northern Great Lakes. At the
surface, a ridge extended from northern Ontario through the western
Great Lakes with a weak pressure gradient allowing prominent lake
breezes to develop. The North Dakota MCS has fallen apart as it
moved into northern MN leaving a large area of convective debris
cirrus from MN into nw WI. Otherwise, mostly sunny skies prevailed
through the region.
Tonight into Sunday morning, Models suggest that another MCS will
develop over ND or southern Manitoba where the low level jet is
focused near the axis of maximum CAPE. The CAMs have been consistent
in dropping this features southeast into WI while the NAM and
regional GEM have been outliers in bringing shra/tsra into western
Upper Michigan. While the MCS is most likely to track closer to the
CAPE gradient into WI, cannot rule out some shra/tsra on the fringe
of the MCS that may brush the west.
Sunday afternoon, if the leftover clouds and convective debris clear
out by mid afternoon, temps should quickly climb back into the mid
80s inland. The evolution of the morning convection will also result
in uncertainty with the potential for redeveloping tsra in the
afternoon as the sfc trough approaches. MLCAPE values into the 1k-2k
J/Kg range will be possible that could support tsra development near
lake breeze boundaries or if any weak shrtwvs approach.
.LONG TERM...(Sunday night through Saturday)
Issued at 347 PM EDT SAT JUN 29 2019
Rain/thunderstorm chances Sunday evening remain somewhat a mystery
as they will depend on whether or not the NAM`s advertised MCS
materializes. Have gone with chance POPs west and south at 00z to
reflect either the MCS happening (but being delayed), or it not
happening and therefore new convection firing out west before 00z a
la the GFS. After that, the models (except the NAM) converge on
resolving a frontal band of precip from about 06-12z across Upper
Michigan so after that evening lull, bring POPs back up to high end
chance/likely. But ultimately have to admit that there is not a lot
of confidence in how things shake out Sunday night.
Though this front is technically a cold front, the drop in temps
will hardly be noticeable - 850 mb temps come down by about 2-3 C
which means highs will still be in the 80s for most - but with dew
points dropping from the mid 60s to low to mid 50s, Monday will at
least feel a bit more comfortable with somewhat reduced humidity.
It`s a short lived reprieve, however. Southwesterly low to mid level
flow develops Monday evening and begins pumping moisture back
northward into the area ahead of a developing low in Minnesota. What
remains in question is just how far north the precip will get, with
the EC and CMC keeping it just along or just south of the Wisconsin
line while the American models drive it right through Upper Michigan
to Lake Superior. For now, have just chance POPs south and slight
chance north but look for those to come up in future packages. The
system`s timing (the warm sector passing overhead Monday night and
Tuesday morning) does not support severe weather. So while some
elevated thunderstorms are certainly possible (best chances south),
Monday night-Tuesday looks more like a hevay rain threat at the
moment (should the American models verify) given strong moisture
transport and PWAT rising to 1.5-1.8".
Behind this system things dry out for Wednesday and thursday... but
not completely. Quite a bit of model spread still in resolving
subtle short waves so have stuck to the model blend with slight
chance to chance POPs. Therefore, can`t rule out some showers/storms
for the Fourth, but it doesn`t look like a washout at this point.
GFS and EC agree that we finally break out of this hot pattern by
the end of the week with a rather strong cold front either Friday or
Saturday. That means a renewed chance of showers and storms as well,
but not worth getting hung up on the details yet this far out.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 630 PM EDT SAT JUN 29 2019
Expect VFR conditions at all terminals through the entire
forecast period.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 411 PM EDT SAT JUN 29 2019
Patchy to areas of fog will be possible over eastern Lake Superior
tonight. Winds of less than 20 knots can be expected through the
forecast period. The next chance for thunderstorms arrives late
tonight into early next week, with periodic chances persisting next
week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Dense Fog Advisory until 8 PM EDT this evening for LSZ251-266-
267.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...RJC
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service Pueblo CO
317 PM MDT Sat Jun 29 2019
.SHORT TERM...(This evening through Sunday)
Issued at 244 PM MDT Sat Jun 29 2019
Mainly isolated thunderstorms have again developed over the higher
terrain this afternoon, as mid level moisture plume to our west
continues to edge eastward into CO, with some subtle moistening of
low levels as well. Max temps still running on the hot side many
locations, with readings over 100f at Lamar and La Junta as of 3 pm.
Storms will continue to percolate over the mountains into the
evening, with some activity drifting out into the I-25 corridor
after 00z, as HRRR shows a few modest cells along the ern mountain
slopes until around 03z. Gusty winds and lightning remain the main
storm threats, as cloud bases will stay rather high. Most
showers/thunderstorms should then end by late evening, though a few
weakening showers may linger toward midnight along the Continental
Divide, as mid level moisture begins to increase. Plenty of
convective debris cloudiness will linger across the entire area
overnight, keeping min temps rather mild into Sun morning. On
Sunday, upper pattern remains generally unchanged, with elongated
ridge stretching from sw to ne across CO. Recycled moisture and a
slow upturn in precipitable water under increasingly moist sw mid
level flow will lead to more widespread convection across the
mountains and interior valleys Sun afternoon, with most activity
again staying along and west of I-25. Main threat will be lightning
and wind, though potential for brief heavy rainfall on burn scars
can`t be discounted. Clouds and increasing precip will hold back max
temps slightly, especially mountains, though a few spots in the
lower Arkansas Valley may again reach 100f.
.LONG TERM...(Sunday night through Saturday)
Issued at 244 PM MDT Sat Jun 29 2019
Not much change to the forecast thinking over the past 24 hours.
The upper pattern will be dominated by high pressure, stretching
from the Desert Southwest into the Central Plains with broad, weak
southwesterly flow aloft across Colorado. Operational models are
in good agreement and ensemble spreads remain low throughout much
of the extended period.
Sunday night into Tuesday...showers and thunderstorms will be
ongoing over the higher terrain Sunday evening. Lack of steering
flow should help keep storms from moving too much, which will
likely lead to an elevated flash flood through over area burn
scars through the evening hours. Expect this activity to dissipate
with sunset and generally dry conditions expected to prevail into
Monday morning across the region.
By Monday, an upper disturbance is forecast to track across
Colorado. This will help increase the southwesterly flow aloft
which will aid in shifting showers and thunderstorms off the
higher terrain and across the Plains through Monday evening.
Locally heavy rainfall will be possible, and an elevated flash
flood risk is possible on burn scars. As for severe weather, wind
and lightning will be the primary threats in addition to the
locally heavy rainfall. Models in good agreement with this
activity spreading east across the Plains and clearing into Kansas
by Tuesday morning. Overnight, a cold front is forecast to drop
south across the Plains turning flow northerly and ushering
slightly cooler air.
For Tuesday, expect another round of showers and thunderstorms by
the afternoon and evening. Initial development will be over the
higher terrain, with southwesterly flow aloft pushing the activity
off the mountains and across the Plains through the evening hours.
Locally heavy rainfall will once again be possible with an
elevated flash flood threat across burn scars.
Temperatures will remain warm with lower to mid 90s expected over
the Plains for both Monday and Tuesday.
Wednesday into Thursday...high pressure is forecast to build back
across Colorado with drier air moving back over the state. This
will bring drier conditions to the region for both days. Isolated
to scattered showers and thunderstorms, primarily over the
mountains are forecast. These showers and thunderstorms look to be
diurnally driven and should dissipate through the evening hours.
Temperatures will warm back into the lower to mid 90s across the
region.
Friday into Saturday...an upper disturbance passing to the north
will send a cold front south into the Plains on Friday afternoon.
This will turn flow more easterly with cooler air working into the
region. The potential exists for more widespread showers and
thunderstorms for both Friday and Saturday across the region.
There will also be a return to an elevated flash flood risk over
area burn scars due to moist upslope flow across the region.
Mozley
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 244 PM MDT Sat Jun 29 2019
VFR tonight at all terminals with a chance for high based VCTS at
KCOS and KALS from late this afternoon into this evening. A period
of gusty and erratic outflow winds will be possible at all terminals
until sunset, as weak convection drifts off the mountains. On
Sunday, convection will again develop over the mountains around 18z,
and with increased moisture, expect storms to spread across lower
elevations and impact all terminals beginning 20z-21z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOZLEY
AVIATION...PETERSEN
Area Forecast Discussion
National Weather Service Tucson AZ
305 PM MST Sat Jun 29 2019
.SYNOPSIS...High pressure will bring hotter temperatures the next
few days. Lingering moisture from the south will bring a few
afternoon and evening thunderstorms around the area as well,
accompanied by strong gusty outflow winds.
&&
.DISCUSSION...Isolated to scattered showers and thunderstorms
continued to develop late this afternoon. Most of this activity has
been confined to areas near Tucson south to Nogales and east to
around Willcox and Douglas. Very similar location and timing as
depicted by the HRRR model early this morning. The latest HRRR
solution showed a few lingering showers or thunderstorms through 09Z
Sunday which still looked reasonable. Otherwise, Tucson managed to
reach 109 degrees today which was a couple of degrees hotter than
yesterday. Still looking at hotter than normal high temperatures the
next few days as high pressure aloft remains in place. These hot
daytime temperatures along with lingering moisture will keep the
shower and thunderstorm chances in the forecast through early next
week. Thereafter, models suggested a drop off in thunderstorm
chances until late next week into next weekend when moisture
returns.
&&
.AVIATION...Valid through 01/00Z.
SCT-BKN deck AOA 10k ft MSL and another layer of cirrus above
through much of the period. Isol`d to sct -TSRA/-SHRA continuing
this afternoon, at or around KTUS, KDUG and KOLS, particularly near
terrain. SFC wind mainly WLY/NWLY at 6-10 kts with gusts up to 16 kt
around KTUS and KOLS and to the west. To the east, sfc winds mainly
SELY/SLY under 12 kts. -TSRA could produce brief gusty outflow winds
of 30-40 kts. -TSRA/-SHRA expected to dissipate after sunset with
winds becoming light and terrain driven. Much of these conditions
are expected to return tomorrow afternoon. Aviation discussion not
updated for TAF amendments.
&&
.FIRE WEATHER...Lingering moisture into next week will bring
daily shower and thunderstorm chances to the region, particularly
south and east of Tucson up to and beyond the state border.
Convection will be high-based as is typical early in the monsoon
with dry lightning an ongoing concern. The best chance for wetting
rain will generally be across the higher terrain. Gusty and erratic
outflow winds will be possible with any storms, with 20-ft wind
speeds of 30-40 mph not uncommon. Outside of convection, 20-ft winds
are expected to remain less than 15 mph through Monday with elevated
southwest winds developing Tuesday and Wednesday. Daytime humidity
minimums will dip to 10-15 percent through Sunday, with a very
gradual increase in these values occuring next week. High
temperatures through Monday are expected to be several degrees above
normal before dropping to near normal Tuesday through the end of the
period.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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