Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/03/17
Area Forecast Discussion
National Weather Service Albany NY
1046 PM EDT Sun Jul 2 2017
.SYNOPSIS...
Although humidity levels will be slightly lower, a few passing
rain showers or thunderstorms are possible into this evening.
On Monday, a frontal boundary will push through the forecast
area, bringing even lower humidity, although a few afternoon
showers or thunderstorms are possible along the front, mainly
for locations south of the Capital District. A dry and
seasonable Independence Day is in the forecast with low
humidity.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 1045 PM EDT, a squall line has developed and is currently
moving across Lake Erie towards the Adirondacks. Some lightning,
brief heavy rain and gusty winds are expected as the line moves
through the Adirondacks and perhaps portions of the Mohawk
Valley within the next couple of hours. The remainder of the
area should be dry for the overnight period with temps in the
upper 50s and low 60s.
Prev Disc...
As of 745 PM EDT, Some showers have popped up but are quickly
moving eastward across the Greater Capital District and points
south. There hasn`t been any lightning associated with these
showers but cannot rule it out completely for the next hour or
so. So continued mention of isolated thunder in the grids. Also
updated hourly temps and sky cover to reflect recent obs.
Otherwise, the forecast remains in excellent shape in the near
term. Sent updates to NDFD and web servers.
Prev Disc...
As of 400 PM EDT...Broad cyclonic westerly flow
remains in place over the Great Lakes and Northeast. Water vapor
imagery shows a fast moving shortwave is located over the upper
Great Lakes and is headed eastward across Ontario. Despite
plenty of dry air in place within the mid and upper levels, some
isolated to scattered rain showers have developed over western
and central New York, as a response to weak instability
interacting with a lake-breeze boundary and the approaching
shortwave. SPC mesoanalysis show just 250-500 J/kg of surface-
based CAPE and mid-level lapse rates are fairly weak (under 6
C/km), so these showers are having a very tough time getting any
vertical extent.
The 3km HRRR suggest these showers will continue to slide eastward
across upstate New York through the evening hours and may drift
across central parts of the CWA from west to east. In addition, the
nearby upper level shortwave could allow for a shower over the
western and central Adirondacks as well. Any shower would be rather
brief in duration and fairly scattered in coverage, but cannot rule
out a few spots seeing a quick shower this evening. Also, a stray
thunderstorm is possible due to the small amount of instability, but
this will be fairly isolated as well.
After the late evening hours, the chance for showers will end, as
the upper level shortwave continues to move eastward across southern
Canada and into northern New England and instability wanes thanks to
the loss of daytime heating. Otherwise, it will remain partly
cloudy overnight with temps falling into the upper 50s to low 60s.
There should be enough a lingering breeze, along with the passing
clouds to help prevent widespread fog from forming, but totally
cannot rule out some patchy fog in some locations (especially those
valley areas that saw heavy rainfall recently).
On Monday, another disturbance will be sliding within the fast flow
aloft. This feature will be accompanied by a surface cold front,
that will be crossing the area from west to east during the day.
Model soundings suggest 500-1000 J/kg of CAPE may be in place around
Poughkeepsie and the fast-flow aloft should allow for about 30-40
kts of 0-6 km bulk shear. The 3km NAM suggest some convection may
develop just south of the area over PA/NJ and remain just south of
the area, but will need to watch to see if anything develops right
along the frontal boundary, as this could impact far southern parts
of the CWA. For now, will go with slight to low chance POPs for far
southern areas and will continue to closely monitor model trends.
Otherwise, it should be dry with a partly cloudy sky and decreasing
humidity through the day, as the front passes through the area.
Valley areas should reach the low to mid 80s, with 70s across the
hills and mountains. Dewpoints should finally be falling into the
50s from north to south by the early evening hours.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
Overall consensus is for a quiet, tranquil and comfortable
holiday weather across most of the region. The passage of a cold
front may linger near the I84 corridor Monday evening where we
will retain the slight chance for convection. Otherwise, a large
area of Canadian origins high pressure building toward 1025MB
will settle across the northeast corridor through the holiday
and into the mid week period. This will provide mainly clear
skies and comfortable humidity levels as dewpoints will average
into the 50s. As for daytime highs, near seasonable levels with
mainly 70s to around 80F for valley locations as H850
temperatures average close to 10C.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
After a stretch of pleasant weather mid - week, the atmospheric
pattern turn unsettled once again for the second half of the work
into the weekend.
High pressure shifts into New England Wednesday night into Thursday
as a shortwave exits the Midwest and heads into the mid - Atlantic.
Guidance suggests that this high will be stubborn to exit and could
slow the onset of the precipitation, especially in our western New
England zones. There are discrepancies among the models in the
shortwave`s strength (EC weakest, GFS strongest) which will
determine its exact track. There has been a slowing trend among the
models over the past few days for the precip`s onset timing so have
expressed that in the newest forecast with highest POPS in the
Thursday and Friday periods in our western zones and kept most
places dry or low end POPs for Wednesday night. Either way, it looks
like humid conditions return for the end of the week with dew points
rising well into the 60s again and PWATs rising over 1 inch. Given
this moist air mass, widespread rainfall is possible with periods of
steady rain at times, especially in any thunderstorms that
occur.
After this system exits, yet another longwave trough from Canada
takes control of the Northeast ushering in multiple shortwaves for
the weekend. Timing, strength and placement of each shortwave is
uncertain but it does look like the trough should introduce cooler
and less humid air despite the continued threat for
precipitation.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected through the entire TAF period.
Some isolated-scattered rain showers have developed and will
continue to quickly pass across central areas this evening but
should only affect PSF briefly. Instability is limited, so
thunder will be isolated at best. The chance for any showers
should end by midnight. West winds this evening will be around
5-10 kts, with a few higher gusts possible from time to time.
Otherwise, just some cirrus clouds will continue overnight with
light w-sw winds around 5 kts or less.
Mainly dry weather is expected on Monday, although cannot
totally rule out a shower or thunderstorm near KPOU in the
afternoon hours. Otherwise, it continue to be VFR with just few-
sct high level clouds with west to southwest winds at 5 to 10
kts.
Outlook...
Monday Night: No Operational Impact. NO SIG WX.
Independence Day: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: Low Operational Impact. Slight Chance of SHRA.
Thursday: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA.
Friday: High Operational Impact. Likely SHRA...TSRA.
&&
.FIRE WEATHER...
Outside of some widely scattered convection through this evening
and again Monday afternoon along and south of I90, a period of
dry and seasonable weather is expected through the mid week
period. RH values will fall mainly into the 40s during the
afternoon with overnight recovery values generally between 70
and 90 percent.
&&
.HYDROLOGY...
River levels remain elevated after Saturday`s heavy rainfall
over areas mainly along and north of I-90, with a few rivers
still in flood stage. Please refer to our rainfall totals public
information statement and graphic for details. A few showers
and thunderstorms will be possible into this evening and again Monday
afternoon mainly south of I90, but are unlikely to be
hydrological significant as a much drier airmass is in place.
Dry weather is then expected Independence Day into Wednesday.
River forecast points appear to have peaked as a slow receding
is expected as no additional sites are forecast to reach flood
stage.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.CLIMATE...
Glens Falls Airport reported 3.30 inches of precipitation/rain
July 1st, setting a new record. The previous record was 0.64
inches set in 2016. This makes July 1, 2017 the 8th wettest
day for Glens Falls. Note that records date back to 1949.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Frugis/Thompson
NEAR TERM...Frugis/Thompson/JVM
SHORT TERM...BGM
LONG TERM...Speciale
AVIATION...Frugis/JVM
FIRE WEATHER...BGM/Thompson
HYDROLOGY...BGM/Thompson
CLIMATE...
Area Forecast Discussion
National Weather Service La Crosse WI
551 PM CDT Sun Jul 2 2017
.SHORT TERM...(Tonight into Tuesday)
Issued at 200 PM CDT Sun Jul 2 2017
Morning convection all east now, mostly driving by an upper level
shortwave and some low level moisture transport. Farther south, an
area of showers/storms was waning over southern Iowa, with another
bit of upper level energy, instability and moisture transport having
been the main drivers. In between all this lies a west-east running
frontal boundary - roughly along the IA/MN border - which is slowly
sinking southward. Decent convergence along the front, which will
run into +2000 J/kg of SBCAPE (per RAP) across northeast
IA/southwest WI from mid afternoon into early this evening. Expect
showers/storms to fire along the front, and HRRR/RAP/HOPWRF agree.
The deep layer shear holds east, but RAP puts about 30 kts in the 0-
3km layer just north of the front. Instability/shear combo should be
enough for a few stronger storms, with an outside shot of an
isolated severe. Expect some heavy downpours, with potential for
small hail and wind gusts. Relatively dry subcloud layer (per bufkit
soundings) would enhance any gust.
The front continues to sink south on Monday, and should keep any
pcpn threat with it south of the local area. Come Tuesday, all the
models start to bring an upper level shortwave trough east across
the northern plains, creeping across the Upper Mississippi River
valley Tue night. Much of the energy with the feature looks to hold
south, but some of the models suggest enough spin northward that
there would be a shower/storm threat locally. Some drier air to
battle though with easterly winds on the back side of a high over
the eastern great lakes. Confidence a little shaky on how this will
play out, with implications for the 4th fireworks. Any pcpn threat
could hold west/south of the forecast area through Tue night...may
venture into areas west of the Mississippi River...or could spread
into all areas that evening. What looks more likely now is that
there will be at least some small chances for showers/storms Tue
evening across the west - with potential impacts for the evening
festivities.
.LONG TERM...(Wednesday through Sunday)
Issued at 200 PM CDT Sun Jul 2 2017
Models have been in pretty good agreement with taking a shortwave
from the plains and spinning it across the mid mississippi river
valley wed. Differences continue in positioning and strength though -
previous EC runs held the shortwave just south of the local area
while the GFS is a bit more perky and extends the feature`s reach
northward (resulting in rain chances area wide). Latest 12z run of
the EC though, while not as strong as the GFS, is a bit farther
north ala the GFS - thus some rain chances. Will follow consensus
for now.
Meanwhile north of there, another shortwave slips across the
northern great lakes, dragging a surface boundary across MN/WI.
Convergence along the boundary, along with instability and some low
level moisture transport into it point to a shower/storm potential.
Both the GFS/EC favor rain chances Thu, with the GFS holding onto
the boundary and continued chances into Friday. Will let consensus
solution dictate the rain chances.
Looking for some warming for mid/end of the new work week, although
the warmest air is expected to hold west across the plains. Should
see a return to temps closer to the July normals - with Thu shaping
up to be the warmest. GFS/EC cool it down for next weekend, dropping
a trough southward through the region, accompanied by cooler air.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 551 PM CDT Sun Jul 2 2017
A cold front extended across northern Iowa into southern Wisconsin
late this afternoon with an area of high pressure centered over
Manitoba and North Dakota. The front will continue to get pushed
slowly south as the high moves southeast to be centered over Lake
Superior by late Monday afternoon. This will provide a quiet
weather pattern for both airports with VFR conditions expected.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Rieck
LONG TERM....Rieck
AVIATION...04
Area Forecast Discussion
National Weather Service Denver/Boulder CO
808 PM MDT Sun Jul 2 2017
.UPDATE...
Issued at 752 PM MDT Sun Jul 2 2017
Outflow bndry from convection over wrn Nebraska was moving across
the far nern plains but no storms have developed along this
feature. However will leave in low pops thru midnight just in case
a few storms develop. Over the higher terrain there are some
higher based showers but convective activity has ended. Expect any
lingering showers will end before midnight.
&&
.SHORT TERM...(This evening through Monday)
Issued at 328 PM MDT Sun Jul 2 2017
Isolated thunderstorms are moving out of the mountains and across
northeast Colorado this afternoon with microburst activity.
A strong upper ridge will remain in place over the southwestern
U.S. through Monday, keeping warm temperatures in place across the
desert southwest and Colorado. Flow aloft over Colorado will be
light west-northwesterly with enough mid-level moisture present to
allow afternoon thunderstorms to develop again. It should be a
scenario quite similar to the present afternoon, with the showers
initially developing over the mountains and then moving onto the
plains. Gusty winds and light rainfall will be the main products
of the showers. High temperatures across the plains should again
reach the lower to mid 90s, as this typical summer weather pattern
prevails.
.LONG TERM...(Monday night through Sunday)
Issued at 328 PM MDT Sun Jul 2 2017
Models all show the upper ridge center moving into the CWA from
the west and southwest Monday night through mid week. By 12Z
Thursday morning, the upper ridge center is over western and
northwestern Colorado. Weak north and northwesterly flow aloft is
progged. There is benign synoptic scale energy. Normal diurnal
wind patterns seem to dominate through Wednesday night. There is
some moisture around Monday night and again late day Tuesday.
Wednesday dries out somewhat. Precipitable water values range
from 0.50 west to 1.00 inch far east Monday night through Tuesday
night. Wednesday and Wednesday night dry out a tad. Boundary layer
dew points are mostly in the 40s F over the plains with some
lower 50s F near the eastern border Monday night and Tuesday. They
are a bit higher Tuesday night. By mid Wednesday morning through
Wednesday night, they dry out into the mid 30s to mid 40s There
is limited CAPE progged Monday evening. There is more substantial
CAPE over the eastern plains and high country late day Tuesday.
There is less for late day Wednesday, with the highest number over
the mountains. It is pretty warm aloft, lapse rate fields show
caps in place, especially over the plains. Will keep pops pretty
low, mostly 10-30% Monday evening, late day Tuesday and late day
Wednesday in the mountains only. For temperatures, Tuesday`s highs
are 0.5-2.0 C warm than Monday`s. Wednesday`s highs are up
another 0.5-1.5 C from Tuesday`s. For the later days, Thursday
through Sunday, models keep the upper ridge centered over Utah
into western Colorado all four days. There is some moisture
around, mainly for alpine precipitation. Temperatures stay a bit
above seasonal normals all four days.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 752 PM MDT Sun Jul 2 2017
SSW winds have developed at DIA however they could become more wly
by 9 pm as a bndry over the wrn suburbs moves across. Expect winds
will switch back to more ssw between 10 pm and 11 pm. Meanwhile
outflow bndry over the nern plains may affect the airport between
1 am and 2 am with a switch to ely. By 4 am there is a weak
Denver cyclone with latest HRRR showing some potential for
stratus thriugh 8 am. For now will leave stratus out of next taf
and see if HRRR continues this trend the next few runs.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...RPK
SHORT TERM...Dankers
LONG TERM...RJK
AVIATION...RPK
Area Forecast Discussion
National Weather Service Dodge City KS
1023 PM CDT Sun Jul 2 2017
...UPDATET TO SYNOPSIS...
.SYNOPSIS...
Issued at 1022 PM CDT Sun Jul 2 2017
WV imagery indicates a westerly flow aloft prevailing across the
Western High Plains. Near the surface, a lee side trough of low
pressure remains anchored across eastern Colorado.
&&
.SHORT TERM...(This afternoon through Monday)
Issued at 1240 PM CDT Sun Jul 2 2017
Overnight convection has finally dissipated across the eastern
zones as of midday. Rainfall totals of 5-6 inches were recorded in
portions of NE Ellis county. Remnant outflow boundaries from this
activity can be seen on radar imagery, and may play a role in
convective redevelopment this evening. Instability will continue
to mount through this afternoon, as general SEly surface flow
maintains current dewpoint regime under full sunshine. Can`t rule
out an isolated storm through 7 pm, especially near the outflow
boundary, but most locations will be dry.
Confident that another round of scattered thunderstorms will occur
this evening, but confidence on details of coverage, timing and
impacts are quite low. Consensus of 12z NAM and various CAMs,
including the last few runs of the HRRR, suggest several
thunderstorm complexes will arrive in the western zones this
evening, being carried along in the modest NW flow aloft. Forcing
for ascent is weak and not obvious, as such the details of the
thunderstorm forecast are fuzzy. That said, if at least loosely
organized thunderstorm clusters can form as the models suggest,
outflow wind gusts to near 60 mph would be the primary threat.
CAPE and moisture supply appear sufficient to give storms enough
longevity to track at least partly across SW KS overnight. Lows
tonight again in the 60s.
Monday...Little change in airmass or 850 temperatures, with
continued SE winds, so expect temperatures to mirror those
observed Sunday, in the lower to mid 90s. Have higher confidence
on the thunderstorm prospects Monday afternoon and evening, with
some more forcing evident to hang our hat on. Models have
displayed continuity forecasting a shortwave in SE Colorado Monday
morning that will phase eastward over SW KS during peak heating
Monday afternoon through the evening hours. All models agree, with
minor differences, on convective initiation in or near SW KS by
late afternoon, and MCS generation over central Kansas through
Monday evening. Shortwave that will act as a focus for development
is expected to have plenty of moisture and instability to work
with to generate convection. However, we are in the time of the
year when a previous day`s convection has a strong influence over
the evolution of the next day`s convection. For now, SPC`s 5%
wind/hail probability is certainly warranted for Monday, with a
likely upgrade in wind probabilities needed once the location of
bowing segments can become more nailed down. The heavy rain and
flooding threat will also have to be monitored through Monday
evening if the MCS genesis region ends up being our eastern zones
as models suggest.
.LONG TERM...(Monday night through Sunday)
Issued at 205 PM CDT Sun Jul 2 2017
Pop and QPF grids were increased Monday evening and night across
the eastern 1/2 of SW KS, in anticipation of mesoscale convective
system generation in this region. Shortwave responsible for
Monday`s activity is progged by models to be east of SW KS, in
eastern Kansas, by Tuesday. As such, subsidence behind this
feature is likely to reduce convective coverage considerably. In
other words, it appears Monday afternoon and night will be the last
opportunity for significant rainfall for most of SW KS for some
time.
Typical summer weather anticipated next week, with little day-to-
day temperature variation and minimal chances of rainfall.
Afternoon temperatures will hold steady, in the lower to mid 90s,
each day. Certainly hot, but lower 90s is normal for early July.
Medium range models maintain strong upper anticyclone over the
Great Basin and Rocky mountains, Tuesday all the way through next
weekend. In fact, 12z ECMWF has shifted the core of the upper high
further westward during the long term, more over the Great Basin
and Utah. This will be far enough west to keep the heat in check,
limited to the mid 90s at most locations. Also, with the upper
high maintaining a more westerly position, that opens the door for
NW flow to sneak in with occasional surprises from time to time.
Wednesday and Thursday will be dry, but 12z ECMWF and superblend
suggest one such perturbation may be able to gin up some storms on
Friday. ECMWF shows NW flow aloft continuing next weekend for
further rainfall and thunderstorm opportunities.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 606 PM CDT Sun Jul 2 2017
Models this afternoon remain fairly consistent with a cluster of
thunderstorms crossing western Kansas overnight. Exact track and
timing however still remains somewhat unclear. At this time am
favoring the latest HRRR on timing which is close to the thoughts
on timing from the previous shift. Based on this will focus the
best chance for thunderstorms in the Hays area between 03z and
09z, the Garden City area from 06z to 09z, and the Dodge City area
from 06z to 12z. Prior to these thunderstorms the winds will be
southeasterly at 10 to 15 knots and after these storms pass the
prevailing winds will be westerly at 10 to 15 knots. VFR
conditions can also be expected outside these storms overnight.
Strong winds, IFR visibilities due to heavy rainfall, and MVFR
ceilings are likely with these storms as they pass during the
overnight hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 92 67 91 / 20 20 50 10
GCK 65 92 64 92 / 30 10 40 10
EHA 61 95 60 95 / 20 20 20 10
LBL 67 97 65 96 / 20 20 20 10
HYS 67 90 65 89 / 50 20 60 10
P28 70 93 69 90 / 20 20 50 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Burgert
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1147 PM EDT Sun Jul 2 2017
.AVIATION...
An weak mid level short wave passing over a slow moving frontal
boundary will sustain some convection just south of metro Detroit
during the early morning hours. Otherwise, high pressure building in
from the north will provide light winds through the TAF period.
For DTW...The elevated instability axis early this morning will
largely pass just south of metro. There will remain a good chance
for a few high based showers to pass overhead.
//DTW THRESHOLD PROBABILITIES...
* Low in thunderstorms this morning.
* Moderate in ceilings at or below 5000 ft this afternoon.
&&
.PREV DISCUSSION...
Issued at 716 PM EDT Sun Jul 2 2017
UPDATE...
Ascent along the nose of a low to mid level theta e plume within the
entrance region of an upper jet has supported some upscale growth to
the convection across srn Lake Mi. The latest RAP and HRRR suggest a
weak convectively generated mid level impulse will release from this
convection and ripple across far Se Mi in the 03Z to 07Z time frame.
Although the better mid level instability will be shunted to the
south (toward the Mi/Oh state line), enough weak elevated
instability combined with mid level forcing will warrant an increase
in coverage of showers/thunderstorms across metro Detroit/Ann Arbor
and points south tonight.
PREV DISCUSSION...
Issued at 350 PM EDT Sun Jul 2 2017
DISCUSSION...
Enhanced westerly flow around the southern periphery of the low
tracking across the northern great lakes is supporting a poorly
organized band of innocuous shower activity over Lake Michigan and
western Lower this afternoon. This activity will encounter an
increasingly hostile environment for weak convection as it works
into southeast Michigan suggesting nothing more than a low chc pop
will be needed this evening. Total rainfall under 0.05" anticipated
with expectation of diminishing intensity. Confluent flow aloft and
deep layer subsidence build in late tonight through Tuesday
supporting high pressure, enhanced by the lake aggregate, over the
CWA during this time. Only concern of note during this period is
occasional shower/tstorm chances south of the I-94 corridor tonight
into Monday as the mid-level baroclinic zone settles near the MI/OH
border. General expectation is for high pressure to dominate even in
this area given the lack of necessary forcing to draw the reservoir
of instability northward. Moved the forecast forward with just low
chc pop near the border Monday followed by dry wx on Tuesday as dry
air and high pressure dominates. Thermal profile will be typical for
early July, hovering around 10C at 850mb, and supportive of highs in
the upper 70s to near 80 degrees. Cool easterly flow around resident
high pressure will suppress dewpoints to 60 or lower while temps
Tuesday night have a chance to touch the upper 40s in sheltered
locations in the Thumb owing to a diminished gradient under lake
aggregate high pressure.
High pressure will remain in control through much of the day on
Wednesday keeping mainly dry conditions in place. Low pressure
developing in conjunction with a shortwave ejecting eastward from
the Central Plains is still progged to bring the next chance for
rain and thunderstorms late Wednesday into Thursday across much of
SE Michigan. The highest coverage at this time looks to remain
across the southern CWA where the threat for heavy rainfall will
exist. Another round of showers will be possible on Friday as a cold
front drops south through the region. Temperatures will remain near
average through the late workweek with highs in the low 80s. In the
wake of the cold front, high pressure will build over the region
next weekend as a drier, cooler air mass drops south into the region
with highs in the upper 70s.
MARINE...
A weak cold front will track through area today into tonight, but
wind speeds should remain generally below 20 knots. Scattered
showers and thunderstorms expected over Lake Huron into this evening
with additional activity possible further south overnight. Light
northwest winds are then expected on Monday as high pressure builds
into the area. Light and variable winds will persist on Tuesday
under this high with light southeast winds developing on Wednesday
as high pressure exits to the east.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
DISCUSSION...SC/JD
MARINE.......DG
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
940 PM EDT Sun Jul 2 2017
.SYNOPSIS...
High pressure will remain centered over the western Atlantic while a
broad upper level trough persists over the eastern part of the
nation for the better part of the next week. A weak cold front will
linger over the Carolinas and northern Georgia early this week,
helping to generate showers and thunderstorms. Another upper level
disturbance will approach our area toward the end of the week,
further enhancing the coverage of showers and storms at that time.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 930 PM EDT: Coverage of the showers and thunderstorms is
gradually dwindling late this evening, and convective intensity is
rapidly dropping off with the loss of daytime heating. Will ramp
PoPs down more quickly for the late evening/early overnight hours,
but will still feature isolated showers through the early morning
hours in most areas as a light, moist, southerly upslope flow
persists below 850 mb. Anticipate some low cloud and fog formation
in locations that received heavy rainfall this evening, especially
near the Savannah river, the nearby lakes, and the greater
Greenville area. Lows overnight should be a couple of degrees above
normal.
Otherwise, the weather will remain dominated by a weak mid-level
trough over the southeast CONUS that makes little eastward progress
through the near-term period. Surface winds will be light and
humidity high, with solid chances for mainly afternoon thunderstorms
continuing as instability bubbles up to values comparable to today.
A couple of weak upper level disturbances may also help to support
thunderstorms again Monday afternoon. Expect near normal highs
Monday afternoon.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 230 PM EDT Sunday: The showers and thunderstorms, associated
with an upper level wave, a very moist atmosphere, and subtle
surface convergence, will slowly wane Monday night. However, since
there remains some semblance of forcing throughout the night, we
will not completely drop the POPS as activity lingers.
The models appear to have split into two camps for Tuesday and
Wednesday, with the NAM lifting the central Mississippi Valley upper
level low pressure system to the northeast, similar to the old
European model. Meanwhile, the GFS and Canadian models still string
out pockets of energy riding the southern end of the westerlies.
We will follow with the current trend with ripples of energy passing
through our forecast area (FA) through Wednesday. As a result there
will be periods of enhanced POPS, as overall atmospheric conditions
will not have changed. A note worth mentioning, although our POPS
will remain elevated, we have brought them down just a notch,
providing some weight to the NAM and European models. Once again at
night we will adjust POPS down but not completely cut.
Precipitable water values certainly remain elevated, therefore
locally heavy rain will be possible with any of these storms.
The temperature department seems rather stable from the latest set
of guidance, compared to past performance. Therefore only minor
adjustments were needed.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 100 pm Sunday: A long wave trough will become re-established
across the East early in the period, as a relatively strong short
wave migrates from the Ohio Valley into the upper Mid-Atlantic.
Attendant cold front is expected to bring solid chance to likely
probabilities for convection by Thu afternoon. Deep layer shear may
become adequate by the end of the day to support some degree of an
organized severe weather threat, especially farther north across the
forecast area.
Under the influence of weak continental high pressure, the global
models generally depict drier and more stable air filtering into the
area by Friday, suggesting a lull in diurnal convective activity,
although considering the time of year, we opted to maintain small
(sub-climo) pops for PM showers/storms Fri afternoon. However, a
consensus of global deterministic models guidance and their ensemble
systems suggest another short wave trough will cross the
central/northern Appalachians over the weekend, allowing for another
weak fropa for our area, most likely in the Saturday/Sat night time
frame. Pops therefore ramp back up to solid chances Saturday. While
the latest GFS is rather aggressive in building another (relatively)
dry air mass into the region by Day 7, the ECMWF is considerably
slower in pushing the boundary to the south and east of the forecast
area, suggesting another active convective day next Sunday. Again,
taking climatology and this inherent uncertainty into consideration,
opted to advertise chance/near climo pops for the new Day 7. Temps
are forecast to remain very close to climo through the period.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
At KCLT: Convection over Upstate SC continues to wane late this
evening and stands very little chance of reaching the piedmont
around KCLT. Will keep the TAF dry with mainly mid and high cloud
ceilings overnight. Given the boundary layer moisture, some fog will
be possible, but the RAP profiles and MOS do not feature any
restrictions so will keep conditions VFR overnight. Anticipate light
winds coming up slightly with mixing from the SW on Monday. Diurnal
triggering will produce scattered thunderstorm coverage Monday
afternoon and warrant a PROB30 mention.
Elsewhere: The strength of the lingering convention around KGSP
continues to wane late this evening, and expect mainly showers or
light rain through 04Z at KGSP and KGMU, with lesser chances at KAVL
and KAND. KHKY should remain dry so far removed from any outflows.
The best chance of restrictions overnight in the moist boundary
layer will be KAND and the southwest NC mountain river valleys.
However, KGSP and KGMU will need to be monitored for fog formation
given the locally heavy rainfall that occurred today. Anticipate VFR
cigs developing through Monday, with convective chances rising
through the afternoon with improving instability and better
triggering from weak shortwaves aloft.
Outlook: Moist and unsettled weather will continue through most of
the week. Nocturnal restrictions can be expected in locations
receiving heavy rainfall.
Confidence Table...
01-07Z 07-13Z 13-19Z 19-00Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 100% High 100% High 100% High 100%
KHKY High 100% High 100% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 99% High 99% High 96% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...JDL
NEAR TERM...HG
SHORT TERM...TS
LONG TERM...JDL
AVIATION...HG
Area Forecast Discussion
National Weather Service Lincoln IL
854 PM CDT Sun Jul 2 2017
.UPDATE...
Issued at 854 PM CDT Sun Jul 2 2017
A weak disturbance passing through northern Illinois this evening
enabled a line of thunderstorms to form and brush along the
northern boundary of the central IL forecast area north of I-74,
and the weakening remnants of this feature are pushing through
northern Vermilion County late this evening. Otherwise, conditions
are stabilizing this evening as daytime heating ends, and the
only other feature capable of bringing any showers or
thunderstorms looks to be a slow moving cold front over far
northern Illinois, which should remain north of the area through
the night. Have therefore adjusted forecast to be dry the
remainder of the night, other than the outgoing
shower/thunderstorm feature.
Otherwise, light and variable to light W-SW winds expected
overnight, and lows in the mid to upper 60s look good. Updates
this evening mainly for details of evening shower/thunderstorms.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 305 PM CDT Sun Jul 2 2017
A mostly sunny and warm afternoon over CWA with temps in the mid
to upper 80s with a few cities approaching 90F. Dewpoints were in
the low to mid 60s so getting a bit more humid with WSW flow. A
cold front pushing into southern WI south of Madison and Milwaukee
will move southward into northern IL during tonight. HRRR model
is more aggressive with spreading scattered convection eastward
over northern CWA, north of Lincoln during late afternoon and
early evening. Other models are further north and more isolated
with this convection and leaned in this direction with just slight
chances NE of I-74 this evening while better chances will be ne
of CWA where better upper level forcing expected and closer to
surface cold front. Milder lows tonight in the mid to upper 60s.
Dry conditions expected overnight into Monday morning, then have
20-30% chance of showers and thunderstorms during mid/late Monday
afternoon north of I-70 as airmass gets more unstable with
dewpoints rising into the mid to upper 60s. Also have lingering
weak frontal boundary near central IL that will help produce the
isolated convection Monday afternoon. Very warm on Monday again
with highs in the upper 80s to around 90F. SPC day1 to day3
outlooks keeps marginal risk of severe storms out of CWA through
Tue night with weak wind shear present over area.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 305 PM CDT Sun Jul 2 2017
Just isolated convection possible along and north of I-74 on
Monday evening otherwise dry wx expected Monday night over CWA.
12Z GFS models keep some light qpf over parts of CWA overnight
Monday night, but most other models are dry and without much of a
lifting mechanism, think drier is the way to go.
A weak upper level low/trof to track east into the central plains
on Tue, into IA/MO on Wed and into IL Wed night and ohio river
valley Thu. Expect chances of showers/thunderstorms to arrive by
Tue afternoon though best chances will be later Tue night
thru Wed night. Chances of convection diminish from west to east
during the day Thu and mainly lingering small chances east of I-57
Thu afternoon. Seasonably warm and humid conditions to prevail
during mid week, with highs Tue in mid to upper 80s, and 80s on
Wed/Thu.
Northwest upper level flow aloft reestablishes itself over IL on
Thu/Fri, and a weak trough and cold front within the nw flow will
pass through the area on Friday and Friday night. This will bring
20-30% chances of showers and thunderstorms. Not as much moisture
to work with this system to rainfall amounts look much less if
they occur. Weak surface high pressure around 1020 mb to settle
into central and western Great Lakes next weekend bringing drier
and less humid wx along with temperatures cooling a bit below
normal with highs Sat/Sun in the lower 80s and dewpoints in the
mid 50s to lower 60s (after highs in the mid to upper 80s on Fri).
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 705 PM CDT Sun Jul 2 2017
A weak disturbance passing through northeast IL this evening may
affect KBMI-KCMI with a shower or thunderstorm early in the
forecast period, although thunderstorms will likely remain north
of the area overnight with a cold front well north of the area. On
Monday, the cold front looks to settle slowly southward toward the
I-74 corridor and have therefore included VCTS in these TAFs,
however probability of occurrence remains relatively low before
00Z and timing of any storms remains uncertain. Conditions likely
VFR through the period. Winds west generally under 10 kts this
evening shifting to south Monday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...37
SHORT TERM...07
LONG TERM...07
AVIATION...37
Area Forecast Discussion
National Weather Service Northern Indiana
1024 PM EDT Sun Jul 2 2017
.SYNOPSIS...
Issued at 240 PM EDT Sun Jul 2 2017
A frontal boundary will sag south into the region tonight
bringing chances for scattered showers and thunderstorms. Lows
tonight will drop into the mid 60s. Monday and Tuesday will
feature seasonably warm temperatures and mainly dry conditions.
However, there is a low chance for a few showers and storms each
day as a weak front stalls out over the area. Better rain chances
return toward the middle of the week.
&&
.UPDATE...
Issued at 1016 PM EDT Sun Jul 2 2017
Line of showers and thunderstorms which caused some locally higher
wind gusts in a narrow swath across LaPorte county has now
weakened considerably as depicted by consistent runs of the HRRR.
Low level moisture has increased along and behind the line with
dewpoints into the low to mid 60s. Radar signatures shows portion
of the remnant line accelerating across Wabash county, but
Observation in Rochester only showed 25 kts so local wind gusts of
30 to 40 mph will be possible. As for the rest of the night, past
runs of the HRRR shows some possible isolated development of
showers overnight but this has largely disappeared with the newest
runs, likely due to combination of subsidence behind the line and
diurnal capping. With outflow boundaries around, can`t rule out a
stray shower, so will leave slgt chc mention in overnight.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 240 PM EDT Sun Jul 2 2017
Not much change with regard to forecast for this evening and
overnight. Robust shortwave seen on water vapor imagery across
northern Lakes sending a modest cold front through the region.
However, this wave is getting rapidly sheared and absorbed into
larger PV reservoir over Quebec and will cause trailing front to slow
and weaken through the overnight. Still, modest destabilization
noted across northern IL in RAP mesoanalysis with a decent 850-700mb
theta-e ridge advecting into our area. This will be enough to
maintain at least SCT convection across our N/NW zones through the
early evening. Most hi-res guidance agrees current convection over
Lake MI will dissipate but additional storms will develop over
northern IL late this afternoon. Thereafter, loss of diabatic
heating and continual stripping away of mid/upper support for lower
level convergence/fgen will lead to dwindling chances to the south
and east. Most hi-res CAM`s fairly aggressive in cutting off precip
around or shortly after midnight which makes sense given lack of
forceful isentropic ascent or moisture advection. Inherited forecast
reflects this quite well and only minor tweaks needed. Suppose there
is a chance for an isolated strong storm this evening in the NW
given SBCAPE values progged to be around 1500 J/kg with 25-30 kts
deep-layer shear. However, there is a fairly sharp moisture/
instability gradient and with both diurnal and advective component
waning, expect any stronger storms to quickly weaken in our CWA.
Best chances in our far NW counties where some brief heavy rain and
gusty winds are possible around 00Z. Precip chances winding down
after 06Z with overnight lows in the mid 60s given clouds/precip and
higher surface dewpoints.
&&
.LONG TERM...(Monday Night through Sunday)
Issued at 240 PM EDT Sun Jul 2 2017
Remnant boundary will then hang across our area through the middle
of the week and bring at least some low chances for showers/storms
Mon and Tue. Little to no mid/upper support though with slowly
rising heights. Precip chances will depend on diurnal instability to
do much of the heavy lifting, a dubious proposition given lackluster
moisture profiles/surface dewpoints. Latest GFS even suggests a more
aggressive anticyclonic push, forcing boundary and best precip
chances south of our area, or at least south of US-30. Some support
for this in NAM12 and hi-res models so latest consensus init is more
subdued and further S/SW with PoPs. Suspect most of this period will
end up being dry (especially in our N/NE) but some low chances still
warranted. No severe risk given warm temps aloft, limited moisture,
and lack of substantive shear/flow aloft.
Much better rain chances arrive late Wed/early Thu. Models remain
consistent on tracking healthy shortwave through the area, though
still differ with regard to exact timing. Despite a fairly
consistent picture across the deterministic models, confidence is
not high as this wave will likely be modulated by convective trends
upstream. Potential is there for a potent area of CVA with compact
wave and good surface reflection. Still not a great severe signal
but heavy rain possible in this scenario given ample deformation/
fgen in moist environment. Will continue to watch this period
closely given recent heavy rain in some locations but difficult to
nail down details until wave emerges from the Rockies on Tuesday.
Still looks like a cold frontal passage sometime around Fri with
cool/dry/pleasant weather late weekend/early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 705 PM EDT Sun Jul 2 2017
A convergent boundary oriented generally east to west situated
west of Lake Michigan and then moving southeast will serve as
forcing for showers and storms into the early overnight. The late
afternoon state of the atmosphere lacked CAPE and shear, but
contained decent 2-6KM lapse rates. Expect CAPE and shear to
advect into the region from the west tonight, but dissipate around
sunset. This should allow for showers and thunderstorms especially
near SBN in the early overnight with a strong storm or two
possible so will include a VCTS for that time period. A brief
reduction in conditions with heavy rain moving through is also
possible. CAMs show storms entering the NW portion of the forecast
area, but dissipating as they move towards FWA, though a VCSH
can`t be ruled out there. Expect conditions to stay in VFR
overnight with some showers continuing along the boundary as it
becomes situated across the region overnight. More showers and
maybe a thunderstorm are possible again Monday.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...Fisher
SYNOPSIS...Steinwedel/AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Roller
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Area Forecast Discussion
National Weather Service Jackson MS
911 PM CDT Sun Jul 2 2017
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
Hardly any changes have been made to the latest updated, just
some minor adjustments to the POPs in the northwest region for
early morning hours. That upper level short wave that is exiting
out of Oklahoma and entering western Arkansas at the moment will
still be be on our doorstep for the early morning hours. The
latest HRRR run has the system breaking up around the Delta
region by late morning, however some isolated thunderstorms could
still flare up. /12/
Prior discussion below:
Tonight through Monday:
Weather over the ArkLaMiss continues to be influenced by the
southern periphery of the westerlies and a series of shortwave
troughs. One wave and an associated convective system has just
about moved east of the area with drier and more stable air
advecting in behind the system, so expect quiet weather this
evening and into the overnight. The next wave and associated
convective system will move across Arkansas late tonight and
likely weaken as it approaches northwest portions of the ArkLaMiss
before daybreak. However, with precipitable water approaching two
inches Monday, daytime heating could help storms regenerate along
any outflow boundaries, especially along the Hwy 82 corridor.
Farther south and east, rain chances will be less as mid level
ridging has more influence, and greater insolation will make heat
stress the primary concern as heat indices approach 105 in some
cases. /EC/
Monday Night through Sunday:
The primary concern for the Independence Day holiday and the
remainder of the week will be the possibility for dangerous heat
across the forecast area. Max temperatures are expected to be in
the low to mid-90s most afternoons, due to a warm and humid
airmass remaining in place across our region. Combined with
dewpoints around 70 to 75, heat index values are expected to top
out around 100 to 105 degrees in most locations. Heat will be
somewhat tempered in some locations each day by the possibility
of afternoon shower and thunderstorm activity, but peak heating
can still be reached before any thunderstorms may develop.
Thunderstorm potential will be driven primarily by daytime heating
and a series of shortwaves rotating around a strengthening
central CONUS ridge. Best precip chances through midweek will be
across northern and eastern zones in closer proximity to
shortwaves, with a better chance for precip areawide as a frontal
boundary dips into the region next weekend. /NF/
&&
.AVIATION...
00Z TAF discussion:
VFR conditions are expected to prevail through much of the TAF
period. The only exception to this may be a decaying thunderstorm
complex moving into the Delta from Arkansas early Monday morning.
This would likely affect KGLH/KGWO and perhaps KGTR(if it makes it
that far). Have mentioned VCSH at minimum in the Delta TAFs.
Patchy fog may be possible in the morning at some spots. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 73 92 73 93 / 1 15 10 14
Meridian 71 92 73 92 / 1 24 15 21
Vicksburg 74 92 73 93 / 2 8 6 10
Hattiesburg 73 95 73 94 / 1 12 8 13
Natchez 74 90 73 91 / 1 4 5 10
Greenville 74 89 74 92 / 6 39 24 20
Greenwood 73 89 73 90 / 2 45 28 32
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
12
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
603 PM CDT Sun Jul 2 2017
.SHORT TERM... (Through Late Monday Afternoon)
Issued at 342 PM CDT Sun Jul 2 2017
Low temperatures should be slightly warmer tonight with
southeasterly surface winds, albeit weak as the surface ridge across
southeastern MO and IL shifts eastward. A cold front extending from
WI southwest through northern IA will sag southward tonight, but it
appears that convection associated with this feature will remain
north of the forecast area. The HRRR model runs depict an MCS
impacting southwestern MO late this evening and overnight, but it
appears that most of this convection will remain southwest of our
forecast area tonight. For now will include mainly slight chance
pops across a small portion of northeast MO and west central IL and
also across a portion of central and southeast MO late tonight.
Southerly low level winds will lead to slightly better low level
moisture and instability on Monday with slightly more humid
conditions as surface dew points creep up. It appears that the best
chance for convection will be across southeast MO ahead of a
shortwave or MCV, but could not rule out isolated afternoon
showers/storms across much of the forecast area.
GKS
.LONG TERM... (Monday Night through Next Sunday)
Issued at 342 PM CDT Sun Jul 2 2017
The synoptic pattern at the start of the long term period will
feature generally weak northwesterly flow aloft. This regime will
continue through the majority of the period, bringing a few chances
for showers/storms as PV anomalies slide through the flow aloft.
Monday night will likely start off mostly dry. The latest guidance
has trended slower with the approach of an upper level low/PV
anomaly which will be located across the central Plains Monday
night. Given this location, the better isentropic ascent associated
with the low-level jet will focus into the theta-e boundary located
across KS and southwest MO. This should keep any MCS activity
mainly to the southwest of the area Monday night.
Guidance diverges a bit for Tuesday, with the NAM a fast outlier
with the approach of a surface low associated with the PV anomaly.
The NAM appears highly suspect and likely contaminated by convective
feedback issues, thus have favored more of a GFS/ECMWF solution for
precipitation chances and QPF. These preferred solutions suggest a
moistening of the boundary layer through the day on Tuesday as a
warm front lifts northward across the area. This low-level
moistening will lead to building MLCAPE values throughout the day.
However, given the slower progression of the upper-level trough, the
region will actually lie within shortwave ridging during the day on
Tuesday. While convergence along the weak front should be enough to
focus isolated to scattered afternoon convection, it looks as if
coverage may struggle to exceed 30-40% (less coverage than it
appears 24 hours ago).
By late Tuesday night and especially into Wednesday, the trough will
slowly slide through the region. PWAT values near 2 inches, deep
warm cloud depths, and fairly slow storm motions continue to suggest
the threat for locally heavy rainfall late Tuesday night into
Wednesday. The highest precip totals will likely be across
northeast MO, an area that saw fairly heavy rains last week, thus
some minor flooding issues may be possible in this area.
The upper trough and associated surface cold front will have pushed
east of the region by Thursday morning, allowing for drier
conditions to move into the area. However, the upper-level flow
will veer more to the NNW by Friday, allowing for a slow-moving
backdoor cold front to make progress into the area Friday into the
upcoming weekend. The presence of this front will provide
additional storm chances Friday before it pushes through for the
upcoming weekend allowing for the return of mostly dry conditions.
KD
&&
.AVIATION... (For the 00z TAFs through 00z Monday Evening)
Issued at 551 PM CDT Sun Jul 2 2017
VFR through the period with occasional cirrus and diurnal cumulus
clouds. Wind speeds will remain light overnight due to the
influence of a high pressure center. Winds will take on a more
southerly direction with time, especially after 12z when the high
pressure center has moved eastward.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
952 PM EDT Sun Jul 2 2017
.SYNOPSIS...
Bermuda high pressure will remain anchored offshore through
late week, with a weak surface trough of low pressure over
central North Carolina. A series of weak upper level disturbances
will move through the region Monday night through Tuesday
night. A weak front/trough will move over the area on Wednesday
and dissipate by Thursday. Another front will approach for next
weekend.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
As of 950 PM Sunday...Convection continues to linger along the
Albemarle Sound/Northern Outer Banks region late this evening.
Will continue with high chance PoPs for this area for the next
couple of hours as the convection gradually dissipates. High-
resolution HRRR and RAP models indicate some convection develop
over the southern zones toward morning and will indicate chance
PoPs southern and coastal sections after about 09z. Given
precipitable waters above 2 inches on this evening`s sounding,
think any storms that form will have the potential to quickly
drop some heavy rainfall. Another very muggy night with most
of the CWA dropping into the mid to upper 70s with very high
dewpoints.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
As of 3 PM Sun...High pressure will continue offshore with deep
moisture in place. Little change to pattern Monday, other than
trough inland strengthening a bit and slightly better forcing.
Scattered showers and thunderstorms possible throughout the day.
During the first part of the day, think best chances will be
across the southern half of the area then transitioning to
better chances inland and along Highway 17 area during the
afternoon/evening per NSSL WRF. Will keep high chance/likely
pops inland and chance along the coast. An isolated strong pulse
type storm with gusty winds and frequent lightning possible,
though main threat still looks like it would be brief heavy
rainfall with PWAT values around 2 inches.
Heat and humidity continues, though may be a degree or two
cooler than Sunday with more cloud cover. Low level thickness
values support highs in the low 90s/around 90 inland and upper
80s along the coast. Combined with dewpoints in the 70s expect
heat index values around 100 degrees during the afternoon.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
As of 300 PM Sunday...High pressure will remain anchored off the
coast through the period, with typical summer pattern persisting
across the region. A series of weak upper level disturbances will
move through the region from Monday night through Tuesday night,
bringing an increased chance for showers and thunderstorms. A weak
front/trough may move into the area and dissipate Wednesday with
another frontal boundary approaching the area next weekend.
Monday Night through Tuesday Night...Scattered showers and
thunderstorms will continue to be possible Monday in typical
offshore ridge/inland trough synoptic pattern. Guidance now in
modest agreement that a series of weak upper level disturbances will
move through the Carolinas in west-southwest flow aloft during this
time frame, which when coupled with PWATs above 2 inches, warrant
PoPs increasing slightly during the period. Timing of vortmax/short
wave troughs is very difficult at this time, so generally have high
chance PoPs Tuesday for inland portions, transitioning to the coast
for Tuesday night. Confidence not high enough to go any greater than
30 to 50 PoPs this period across the area at this time. Future
updates may adjust upward. Isolated strong pulse type storms will be
possible given very moist column with decent instability, though
little shear available as noted in forecast soundings with less than
15 kts of 0-6km shear. Main threat remains locally heavy rainfall
with only a small chance for any severe storms. Reduced max temps a
few degrees on Tuesday due to expected cloud cover and
precipitation. High temps will range from the mid to upper 80s
inland to mid 80s near the coast, with overnight lows in the 70s.
Wednesday...A weak front may drop into the area Wednesday, then
washout. Models differ slightly about exactly how far into the area
this front progresses. Regardless, the front will help focus
precipitation and increased PoPs, to 40 to 50 across the area.
Thursday through Sunday...Weak upper ridging and surface high
pressure offshore will continue through late week. This pattern
would produce mainly scattered diurnally driven showers and storms,
with best chances inland during the afternoon and evening,
transitioning to better chances along the coast during the overnight
hours. Upper ridge will begin to break down late week and next
weekend as upper trough pushes into the eastern US. Models show a
cold front pushing south into the area Saturday into Saturday night,
which could provide additional focus for convection. The GFS is much
more progressive bringing the front well through the area while the
ECMWF hangs it up along the coast. Favored a WPC solution with a
blend that seems to favor more of the ECMWF solution. Will keep
slight chance to chance PoPs, mainly diurnally driven, during the
period. Highs will generally be in the low 90s inland with mid/upper
80s coast, with lows in 70s.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Short Term /through 00Z Tuesday/...
As of 645 PM Sunday...VFR conditions should continue through
the evening into the overnight hours as convection continues
well NE of the TAF sites. MET guidance and model time sections
hint at a period of MVFR ceilings early Monday morning. Winds
may also decouple briefly in the morning which may produce
patchy fog, although debris high cloudiness and developing early
morning showers to the east of the TAF sites may prevent much
fog. Will forecast MVFR conditions from about 09z to 12z Monday
morning. Conditions quickly return to VFR Monday morning.
Scattered showers and thunderstorms will develop again Monday
afternoon, but not enough confidence to include VCTS at this
time as extent of coverage hard to pinpoint.
Long Term /Monday night through Friday/...
As of 300 PM Sunday...VFR conditions are expected to prevail
through the period. Some brief sub-VFR periods are possible
throughout the period, mainly in scattered afternoon and evening
showers and thunderstorms. Also, cannot rule out some brief
periods of sub-VFR fog/low stratus during the pre-dawn hours
each morning.
&&
.MARINE...
Short Term /through Monday/...
As of 950 PM Sunday...SW remain gusty on the coastal waters, but
have gone to more SE/E on the Sounds briefly, but should veer
back around to S/SW toward morning. Speeds continue at 10-20
knots with a few higher gusts, especially in offshore
convection. Seas are running 2-4 feet. The gradient between
Bermuda high pressure offshore and the Piedmont trough inland
will continue to produce S/SW winds 10-20 knots with seas at 2-5
feet Monday.
Long Term /Monday night through Friday/...
As of 300 PM Sunday...Fair boating conditions expected Monday
Night through Wednesday as Bermuda high remains anchored off the
SE coast. Could see a weak boundaries drop into the northern
waters Wednesday, briefly allowing the winds to shift to E/SE,
but expect southwest to south winds will remain the predominant
directions through the period, at around 5-15 kts.
By Thursday, winds will begin to increase a bit as the gradient
tightens between high pressure offshore and a slowly approaching
front to the west. Winds will increase to 10 to 20 KT on Thursday
and 15-25 kts Thursday Night into Friday. Seas will generally be 2-4
ft through the long term, though some 5-6 ft seas are expected
across the outer central and southern waters Thursday Night into
Friday.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...CQD
NEAR TERM...CTC
SHORT TERM...CQD
LONG TERM...RSB
AVIATION...RSB/CTC/CQD
MARINE...RSB/CTC/CQD
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1056 PM CDT Sun Jul 2 2017
.UPDATE...
Issued at 1048 PM CDT Sun Jul 2 2017
Updated to include 06z aviation discussion below.
&&
.SHORT TERM...(This evening through Monday)
Issued at 415 PM CDT Sun Jul 2 2017
The weather today is nothing short of spectacular, with the front
that came through last night just now pushing down into northern
Iowa. Given the fronts current location, we like what the HRRR
shows with storms this afternoon firing off 2 or 3 counties
south of the MN/IA border. We`ll see no precip through the night
as high pressure currently to the northwest slides through. We
will have clear skies, light winds, and with dewpoints this
afternoon mixing down into the upper 40s/lower 50s, we`ll have no
trouble cooling back comfortably into the 50s tonight, save for
the core of the Twin Cities urban heat island, which will stay a
few degrees warmer than the rest of the area.
The weather tomorrow won`t be much more exciting, as the front
clearing MN now will stay in IA, keeping any diurnally driven
activity to our south. Out west, the weak and elongated trough
currently working through the Rockies will be going across the
Dakotas, though any precip with it will be staying off to our west
until Monday night. Looks good for highs getting up to around 80
as well. It will be one more nice day before the humidity and
precip chances increase for the fourth.
.LONG TERM...(Monday night through Sunday)
Issued at 415 PM CDT Sun Jul 2 2017
The main questions for the long term concern the potential of
storms Monday night through Wednesday, and warm temps Thursday
with upper ridge looming to the west.
Models have converged upon bringing a short wave into Minnesota
on Tuesday. It appears said wave is now over Idaho. It does not
look strong by any means, and winds throughout most of the column
will only be 10-30 knots, but MN/WI will be in a favorable right
entrance region of a 40-50 knot jet over the Great Lakes. Thermal
profiles look OK, but there certainly will be plenty of low and
mid level moisture streaming into MN and then WI. In fact,
precipitable water values are generally around 1.6 to 1.8 inches
late Tuesday afternoon, with some suggestions that it may wind up
even higher. This indicates storms are a good bet for western into
central MN on Tuesday into Tuesday evening. Pops are now in the
40-50 percent range for this area. Coverage will be scattered, so
not every spot will get rain. But where it does rain, there could
be a downpour with slow moving storms lasting an hour or two, and
with lots of available moisture. Somewhat dry air will keep
western WI dry on Tuesday evening, and maybe eastern MN, with
easterly winds persisting due to the high pressure still over the
eastern Great Lakes. But the rain chance will spread eastward late
Tuesday night and Wednesday.
After the short wave, there will be a respite for about 24-36
hours before another short wave arrives, mainly Thursday night.
This will definitely be much stronger, with the upper jet 80-90
knots as it traverses the northern edge of the broad western upper
high. There will still be an abundance of low-mid level humidity,
so this will need to be watched for storms. Closer to the upper
high, lots of sun in southwest MN and a westerly flow ahead of the
cold front, could result in temps soaring quite a bit. As it is,
bumped max temps to 90 for sw mn on Thursday. This may not be
enough, but there is plenty of time to adjust.
The energetic short wave Thursday night reinforcing the eastern
trough, together with the western high retrograding slightly,
will mean seasonable temps Fri- Sun, with hints of another wave
and 100 knot jet arriving on Sunday. It`s much too early to say
whether MN/WI will bear the brunt of this or just get sideswiped.
Either way, it seems the western ridge will edge closer after
that, with a lot of time to assess that.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1048 PM CDT Sun Jul 2 2017
High pressure will prevail across the region throughout this
03/06z TAF set. Passing high clouds will be the only concern,
potentially creating ceilings from time to time but at levels at
least 15 kft if not higher. Winds will run less than 10 kt
throughout with directions eventually settling on southeast by
tomorrow afternoon.
KMSP...No significant weather impacts expected.
/OUTLOOK FOR KMSP/
Tue...Mainly VFR. Chc -TSRA/MVFR. Winds SE 5-10 kts.
Wed...VFR. Winds S 5 kts.
Thu...VFR. Winds SW 5 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
UPDATE...JPC
SHORT TERM...MPG
LONG TERM...TDK
AVIATION...JPC
Area Forecast Discussion
National Weather Service Omaha/Valley NE
610 PM CDT Sun Jul 2 2017
.SHORT TERM...(Tonight through Wednesday)
Issued at 245 PM CDT Sun Jul 2 2017
Persistent area of showers and thunderstorms that has been
hanging over southeast Nebraska and southwest Iowa since this
morning continue to gradually sink south at 19Z while new cells
develop upstream near a Columbus to Albion line. Latest satellite
loops also show growing cumulus along surface boundary from
northwest Iowa into northeast Nebraska where it intersects the NW-
SE oriented band of developing storms.
Operational HRRR has been doing pretty well with depiction of
storms over the area today and latest run ( 18Z ) shows activity
gradually dissipating through the remainder of the afternoon as
it drifts south. Storms over central Nebraska become dominant
after 00Z as they drop south into Kansas, while eastern Nebraska
and southwest Iowa stay dry. Have generally reduced PoPs for
tonight into Monday with northern parts of the area having
somewhat better chance of storms as next upper wave approaches
Monday afternoon and evening. Storm chances then hang over the
area Monday night into Tuesday as upper wave splits into a
northern and southern configuration. As a result highest PoPs are
expected near the northern and southern borders of the forecast
area. Heavy rain was reported with the storms this morning across
Seward county due to training and regeneration and the potential
for additional heavy rain should continue for the area through
Tuesday as Precipitable Water from 1.5 to 2 inches will remain
over the area.
Drier but warmer conditions then move into the area on Wednesday
as the western ridge expands into the central plains.
.LONG TERM...(Wednesday night through Sunday)
Issued at 245 PM CDT Sun Jul 2 2017
Trend toward warmer and dry conditions will stretch into the
first part of the extended period before western ridge shifts west
by the weekend with area again coming under influence of stronger
northwest flow and increasing chance of storms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 610 PM CDT Sun Jul 2 2017
As of 23z, mesoanalysis depicted a weak surface boundary stretched
generally west-to-east across far northeast Nebraska and northwest
Iowa with little net movement to this feature. Widely scattered
showers and thunderstorms have attempted to become established
along this boundary this afternoon, however weak low-level
convergence is likely preventing this from happening. As such, it
appears that dry conditions will prevail at all three TAF sites
through the forecast period. The boundary may settle south some
tonight and areas of low clouds and fog are possible around
daybreak Monday.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Fobert
LONG TERM...Fobert
AVIATION...Mead
Area Forecast Discussion
National Weather Service Blacksburg VA
754 PM EDT Sun Jul 2 2017
.SYNOPSIS...
A weak stationary front will linger across North Carolina tonight
into Monday before dissipating. Another weak cold front
backdoors into the Ohio Valley Monday afternoon and across the
area by midweek.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 750 PM EDT Sunday...
Isolated showers near Danville at 7PM. MSAS analysis showed
remaining instability mainly over Henry, Pittsylvania,
Rockingham, and Caswell Counties. Any precipitation expected to
dissipate before 11PM. Otherwise expecting some clearing this
evening under weak high pressure as some slow drop in dewpoints
occurs behind the weak surface front. This may allow temps to
fall a bit more overnight with more in the way of 60s, and even
some 50s in the deeper valleys where some patchy fog will be
possible.
Area to remain along the base of a wavy upper trough to the
north Monday and just north of the fading surface boundary to
the south. Although still appears will be in between most
passing energy aloft, guidance suggests the tail of a mid level
speed max will pass across during the afternoon which may
attempt to swing higher PWATS back north. Since seeing some weak
convergence and better instability for the moment near the VA/NC
border, plan to keep the trend of chance pops mainly far
south/southwest into Monday afternoon, with less east per faint
northeast flow, and little north half where drier air aloft
looks to prevail. Should still be quite warm with highs well
into the 80s west and around 90 east. Only exception could be
near the NC border where more early clouds and shower development
may hold highs a category or two cooler than today.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 205 PM EDT Sunday...
An upper level ridge in the western Atlantic will continue to block
and keep our weather pattern slow and basically unchanged through
the period. This blocking ridge will influence the weather from
Kentucky to Virginia southward. To the north, weather systems will
be slightly more progress.
Monday night into Tuesday, a weak upper level trough will reside
over the southern Ohio Valley into the Tennessee Valley. A surface
back-door front will stall along the Mason-Dixon line. A theta-E
boundary will also stall along the hwy 460 corridor. South of this
theta-E boundary, dew points will be in the upper 60s while north
will be closer to 60F. Impulses from the upper level trough will
bring a low chance for showers to areas south of the boundary with
the higher probabilities being in North Carolina Monday night into
Tuesday morning.
Through the day Tuesday, most models are allowing the back-door
front/wedge to side into the eastern portion of the area. That is,
at least the surface boundary with winds becoming northeasterly
through the day. The 850mb boundary stays north over the Mason-Dixon
line through Wednesday morning then retreats north. Without
convection along the boundary, fronts/wedges that lack dynamics have
a tough time moving south during the day, especially into a very
warm air mass. With the models bring a surface wedge into the
region, the winds become easterly with convergence along the Blue
Ridge. This will enhance the chance for orographical storms to
develop and spread across the area. Since we are not confident with
the wedge and easterly flow over the area Tuesday afternoon, storms
should be initiating west of the Blue Ridge and diurnally driven.
Therefore will keep convection confided to the late afternoon and
evening hours and mainly across the mountains. Steering flow may
take these showers east into the foothills during the evening.
The surface wedge has a chance to drop south across the area
Tuesday night, which will bring the needed convergence along the
Blue Ridge for more areal coverage of storms over the region on
Wednesday. Heights increase aloft and storms may have a tough time
starting, but once one goes, more should follow. We should see more
storms Wednesday afternoon than Tuesday afternoon.
Temperatures through the period will run slightly warmer than normal
with afternoon highs in the 80s and near 90F across the piedmont.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 220 PM EDT Sunday...
The upper level ridge in the western Atlantic continues to be a
blocking force for the Mid Atlantic and southeastern states.
However, to the north, the models are more progressive. Models
continue to have a disturbance tracking over the upper Midwest
Thursday then across Ohio and Pennsylvania Thursday night. Models
continue to keep the stronger storms along the track of this
disturbance. The trailing cold front will bring the chance for
strong storms to the region late Thursday afternoon into Thursday
night. High pressure builds in Friday with the next front on
Saturday. Not much is expected from Saturday`s front as the
environment will not have much time to replenish and recover.
Over the last 3 day, models have be persistent on the track of the
disturbance and a frontal passages Thursday and Saturday. Confidence
is increasing for the threat for storms Thursday. However, timing on
the first frontal passage does seem to wavier a bit from Thursday
afternoon to Thursday night. The timing issue will become clearer
with each passing day.
Temperatures will fall back to normal level following the passing of
the front Thursday.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 745 PM EDT Sunday...
Expect any convection to fade before 11PM/03Z giving way to
mainly clear skies overnight. Due to rainfall earlier Sunday
plus lingering weak upslope expect fog at KLWB, perhaps a brief
period of LIFR in fog/stratus before daybreak Monday. Also
include a period of late night MVFR at KBLF and KBCB.
RAP guidance was showing weak southeast wind along the southern
Blue Ridge after 12Z/8AM on Monday. But,only a few of the
models were showing the potential for MVFR clouds along the Blue
Ridge and into the foothills south of Roanoke.
Weak front will linger just south of the area on Monday. Best
instability and the most likely location for scattered to
isolated thunderstorms will be south of the Virginia/ North
Carolina border after 2PM/18Z.
Extended Aviation Discussion...
The residual boundary will remain just south of the region on
Tuesday as another front dips south toward the area by midweek.
Upstream disturbances will likely impinge upon the moisture and
this next frontal boundary to result in added afternoon/diurnally
driven convection. Periods of MVFR cigs will be possible in
this activity, most numerous initially closer to the NC/VA
border, but likely impacting all areas as the week progresses.
Late night and early morning fog can also be expected with
increasing probability through the week, especially given the
increasing potential for late day/evening rain at many TAF
sites. Convection may become more numerous toward the end of the
week as a stronger upper-level system approaches from the west.
All- in-all, likely to be an unsettled week, but periods of VFR
can certainly be expected.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AMS/JH