Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/03/18
Area Forecast Discussion
National Weather Service Bismarck ND
1002 PM CDT Mon Jul 2 2018
.UPDATE...
Issued at 957 PM CDT Mon Jul 2 2018
A couple of isolated thunderstorms continue to move slowly across
south central North Dakota from near Bismarck south to the South
Dakota border. This activity is expected to slowly diminish over
the next couple of hours, but the impulse located over eastern
Montana is still expected to enter the state around or after 06z.
Populated precipitation chances through 12z using the latest time
lagged HRRR iteration which seemed to have a decent handle on the
overall current and future coverage of convection. Otherwise, just
blended the latest observations to the forecast.
UPDATE Issued at 631 PM CDT Mon Jul 2 2018
No major changes needed for this update. Just tweaked my
precipitation chances through 06z based on the latest
observations, trends, and high resolution guidance. Scattered
showers and isolated thunderstorms have begun to develop along a
line from just south of Belfield to just south of New Salem. While
storms are in a favorable environment to become severe (MLCAPE
greater than 1000 J/kg and effective shear ranging from 50 to 55
knots) they are having a bit of a tough time organizing, possibly
due to some capping still observed on the 00z Bismarck sounding. A
couple of these storms should eventually be able to overcome the
cap and have the possibility to develop into supercells capable of
damaging winds and large hail. Lack of better low level moisture
and relatively high LCLs will keep any tornado risk at a minimum.
Storm coverage also should remain fairly isolated due to neutral
to slightly rising heights through 06z. A compact vort max will
move into western North Dakota around 06z, likely sparking more
widespread convection across the west and central.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 146 PM CDT Mon Jul 2 2018
A trough continues to develop across the Pacific Northwest,
creating southwest flow aloft over the Dakotas by tonight. The
first in a series of upper level waves in the southwest flow
aloft should move into the Dakotas this evening, continuing later
tonight with even an even stronger wave. In response, lee
cyclogenesis is forecast to develop this evening, while a low
level jet develops through the central Plains east of the surface
low. This will increase low level humidity with dewpoints rising
into the lower to mid 60s in south central ND.
A warm front will continue to lift north today and eventually
stall out around the ND/SD border. The short-term models have been
consistent in developing some isolated cells late this afternoon
across central North Dakota in response to an approaching upper
level short-wave trough and diurnal heating. Then, later tonight a
complex of storms may develop and march across southern North
Dakota in response to another upper level wave and increasing
low- level jet.
The Storm Prediction Center has placed the southern half of North
Dakota in a "Slight Risk" for severe weather. While the best
instability should be just south of the ND/SD border, there will
likely be ample shear and forcing for stronger storm development
and maintenance. At this time it appears hail around quarter size
and wind gusts to 60 mph are the main threats.
.LONG TERM...(Tuesday night through Monday)
Issued at 146 PM CDT Mon Jul 2 2018
Main concerns for the long term are chances for thunderstorms
Tuesday through Wednesday afternoon, some of which may be severe.
The severe weather parameters are even stronger for Tuesday and
Tuesday night. The western upper level trough deepens over the
Rockies Tuesday with a closed low becoming established over
Alberta/Saskatchewan/Montana, continuing the upper level impulses
streaming northeastward into the northern Plains. The surface
warm frontal boundary becomes more well established from
southwestern South Dakota to northeastern North Dakota as the
surface low deepens over Colorado. CAPE values rise to 2000-4000
J/kg in south central and eastern ND Tuesday through Wednesday
afternoon. Tuesday night the strongest upper level waves move
northeast across North Dakota as the upper low begins lifting
northeast ward into Saskatchewan. The Storm Prediction Center has
placed south central and southeastern North Dakota in a "Slight
Risk" for severe weather for the Tuesday morning through Tuesday
night period.
On Wednesday (July 4th), a cold front moves east across North
Dakota. The chance for severe thunderstorms continues Wednesday
with high CAPE and shear across the James Valley. The cold front
is forecast to reach the Red River Valley by late afternoon, thus
the threat of showers and thunderstorms should be over by
Wednesday afternoon over western ND and be over by Wednesday
evening in the James Valley.
Thursday through Saturday, an upper level western ridge builds
behind the exiting of the strong upper low, and this ridge expands
into the Plains. This should result in a shower and thunderstorm-
free period with a warming trend. Look for highs Thursday from
75-85F, warming to 85-95 for Friday and Saturday.
Another strong upper level shortwave moves east out of the Pacific
Northwest Saturday/Saturday night, dampening the upper ridge and
bringing chances of showers and thunderstorms to our area Saturday
night, followed by a more zonal flow across our area Sunday and
Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 631 PM CDT Mon Jul 2 2018
Scattered showers and isolated thunderstorms will be possible this
evening and tonight across the southern third of the state. One
cluster of storms was developing just south of KDIK. This activity
should drift east southeast through the night before another wave
of showers and thunderstorms will enter the state from Montana
around or after 06z Tuesday. These showers and storms will likely
be more widespread across the west and central and last well into
the early afternoon hours on Tuesday. Winds will remain generally
light and variable outside of any thunderstorm activity, and VFR
conditions will prevail with a chance for some MVFR ceilings
across KBIS/KDIK/KJMS late in the period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ZH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...ZH
Area Forecast Discussion
National Weather Service Columbia SC
811 PM EDT Mon Jul 2 2018
.SYNOPSIS...
Weak high pressure will persist across the area through the
middle of the week. Expect mainly afternoon and evening
thunderstorms. Deeper moisture will return for the end of the
week as a cold front approaches from the north.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
There will be ridging at the surface and aloft through tonight.
Area of showers and thunderstorms enhanced by sea breeze front
earlier moving west of the CSRA at 00z. Negative CAPE
developing across the area and with loss of heating do not
expect any more showers overnight. This is supported by latest
HRRR and other high resolution models. Another muggy night with
minimum temperatures in the low to mid 70s. convective debris
clouds in the CSRA should thin out overnight. Some patchy fog
possible mainly along rivers and low lying areas toward morning.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Upper level high will remain over the New England states will
remain dominant through the short term as an upper level low
moves westward toward the SE Coast. With low level easterly flow
through Wednesday night the region will remain hot and humid
with scattered mainly diurnal thunderstorms Tuesday. The threat
of severe thunderstorms will remain low and thunderstorm
development will be suppressed by 700mb temperatures around 10c.
Main concern with thunderstorms will be weak steering flow and
slow movement allowing the high pwat values to produce locally
heavy rainfall. On Wednesday the upper low moving westward will
move into the forecast area and be accompanied by weak short
waves rotating around the low. This will result in some dynamic
forcing on Wednesday allowing for increased chances of
thunderstorms through the day and evening. With a bit increased
shear Wednesday the potential for strong thunderstorms will be
marginally higher. Temperatures through the short term will be
in the low to mid 90s for afternoon highs with low to mid 70s
for overnight lows.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Upper level low will be over the SE US through Thursday and
weaken as it slowly crosses the area. The synoptic scenario will
begin changing Friday and the upper level high shifts into the
northern Atlantic Ocean and and upper level trough swings into
the Great Lakes region. Through the day Friday and early
Saturday a cold front will drop through the Ohio Valley and
toward the forecast area Saturday afternoon Have trended toward
the ECMWF for the long term as the GFS aggressively pushes the
front southward and through the forecast area late Saturday. The
ECMWF brings the front toward the forecast area then stalls it
just north and shears it apart through the weekend and into
early next week. This will keep chances of showers and
thunderstorms in the forecast each day. Temperatures through
the long term will be near to slightly above normal with daytime
highs in the low to mid 90s and overnight lows in the low to
mid 70s.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A sea breeze will move across the forecast area this evening
keeping SE winds up through 03Z or so. Additional convective
development is not expected with synoptic scale subsidence over
the area. Abundant low-level moisture will support patchy fog
or areas of low stratus early Tuesday morning. Model guidance
suggests that restrictions will be more likely in the CSRA.
Portions of the CSRA also received some rainfall this afternoon
which should increase chances. The most likely scenario may be
similar to last night with a few hours of MVFR or IFR
restrictions at AGS, DNL and possibly OGB from 10Z to 14Z.
Easterly flow will pick up Tuesday morning from 5 to 10 knots with
scattered and mainly diurnal thunderstorms during the
afternoon.
EXTENDED AVIATION OUTLOOK...Restrictions possible each day in
early morning fog and stratus with diurnal thunderstorms.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Duluth MN
655 PM CDT Mon Jul 2 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 331 PM CDT Mon Jul 2 2018
Forecast focus in the short term will be on severe storm potential
and heavy rain.
Warm air and moisture advection has led to a few showers this
afternoon over the Brainerd Lakes, Pine River, and Longville
areas. These showers should continue to move north this afternoon
and a few thunderstorms will develop as well. A southerly low
level jet will develop this evening and will lead to increasing
coverage and intensity of thunderstorms across portions of the
Northland tonight, mainly from the Brainerd Lakes area northeast
through the Iron Range, Twin Ports, and Arrowhead. MLCAPE values
are forecast from 1000-2000 J/KG and deep layer shear will be from
40-50 knots. Some of the storms could be severe with damaging
wind and large hail the main threats. The evening KBRD RAP
sounding shows favorable low level hodographs for a possible
tornado as well. In addition to the severe threat will be heavy
rain. PWAT values are forecast to increase to 1.6 to 1.75 inches
tonight. Storm motions generally from west southwest to east
northeast will lead to training storms so we opted to issue a
Flash Flood Watch for a portion of the Northland, roughly from the
Brainerd Lakes into the Arrowhead from this evening and to 12Z
Tuesday. Confidence in widespread heavy rain is not particularly
high tonight, but there are enough ingredients present for a
watch. The storms should weaken late tonight into Tuesday morning
and the focus for additional development will shift north through
the day with highest chances for showers/storms occurring north
of Highway 2. Storms on Tuesday may also produce heavy rain.
We have highs Tuesday from around 80 far north to the middle
eighties over northwest Wisconsin. Dewpoints will increase to the
sixties with a few around 70 in the Brainerd Lakes region.
.LONG TERM...(Tuesday night through Monday)
Issued at 331 PM CDT Mon Jul 2 2018
Several rounds of thunderstorms are possible from Tuesday evening
through Thursday morning. Quieter weather is expected Thursday
afternoon through Saturday, with a few showers and storms
possible Saturday night and Sunday. Heavy rain and strong to
severe thunderstorms are possible Tuesday night, and again
Wednesday afternoon and evening.
A baroclinic zone is forecast from western Nebraska to northern
Minnesota and northwest Ontario Tuesday evening. Southerly flow
at the surface will veer southwesterly with height. Convergence
is forecast to increase in the vicinity of the front over
northern and northwest Minnesota as a low-level jet develops. A
few strong to severe storms are possible Tuesday night and
Wednesday morning with most-unstable CAPE values around 1500 to
2500 J/kg and deep layer shear on the order of 40 to 45 knots.
Heavy rain will also be possible with PWATs around 1.75 inches.
Moisture transport vectors are oblique to the forecast storm
motions, so training are possible, but not especially likely.
With recent rainfall over the past week or two, the potential
exists for localized flash flooding.
The Northland will remain in the warm sector Wednesday ahead of
an approaching cool front. Weak forcing over the area Wednesday
afternoon and warm 700 mb temperatures suggest capping will
remain in place until the arrival of the cool front in our
western zones late Wednesday afternoon or early Wednesday
evening. MUCAPEs of 1000 to 3000 J/kg are expected with deep
layer shear between 35 and 45 knots raises the potential for
supercells initially, shifting toward multicells as convection
becomes widespread along the front. The SPC has outlined the area
in a Slight Risk of severe thunderstorms and we agree with that
assessment. There will be a possibility for heavy rainfall once
again with PWATs between 1.7 and 2 inches. While the storms
Wednesday afternoon through Thursday morning should be farther
southeast than the storms Tuesday night, a potential for flash
flooding will exist.
After any lingering showers depart northwest Wisconsin Thursday
morning, a dry period is expected as high pressure builds into
the Upper Midwest. Thursday afternoon through Saturday should be
quiet as the ridge gradually drifts from the Canadian Prairies
and Northern Plains Thursday morning into the Ohio Valley by
Saturday evening. A shortwave trough is forecast to move through
the region Saturday night and Sunday with a weak cool front
sliding east-southeastward into Monday. Showers and thunderstorms
will be possible once again from late Saturday night through
Monday as the boundary passes by.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 653 PM CDT Mon Jul 2 2018
VFR with increasing chances of MVFR/IFR as shower activity
intensifies. Short term models show quite a bit of rain between
now and 18Z Tue. VFR should return afterwards.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 62 83 61 82 / 60 40 20 50
INL 58 80 67 82 / 20 70 50 50
BRD 66 84 70 85 / 70 30 30 50
HYR 66 87 67 86 / 20 10 10 40
ASX 64 85 61 84 / 20 10 10 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...Flash Flood Watch through Tuesday morning for MNZ012-019-020-025-
026-033>037.
LS...None.
&&
$$
SHORT TERM...Melde
LONG TERM...Huyck
AVIATION...Wolfe
Area Forecast Discussion
National Weather Service Grand Forks ND
1000 PM CDT Mon Jul 2 2018
.UPDATE...
Issued at 950 PM CDT Mon Jul 2 2018
Storms have formed with hail the primary impact with multiple
reports of hail greater than an inch and up to 2.8 inches in SE
ND. Expecting the strongest storms to continue to move to the
east northeast from Fargo to the SD/ND border.
UPDATE Issued at 818 PM CDT Mon Jul 2 2018
Severe thunderstorm watch has been issued for SE ND and Wilkin Co
in MN until 2AM. Primary concerns will be winds up to 70mph and
hail up to 2 inches. Activity is slowly organizing and scattered
along a line from Park Rapids MN to near Gwinner ND. Potentially a
couple rounds of convection to watch over the next 5 to 6 hours
with current storms and then storms to the west as they move into
SE ND around midnight.
UPDATE Issued at 646 PM CDT Mon Jul 2 2018
Continuing to sit an wait for convection to develop across the
southern portions of the Red River valley. Given satellite trends
and mesoanalysis isolated to scattered storms should develop in
the next hour or two. Thinking 700mb height rises late this
afternoon have kept activity in check. Agitated CU field in SE ND
showing some enhanced towers over the past hour. Will continue to
monitor. Also will be watching area in SW ND and its evolution for
expansion and or increase of PoPs for the overnight.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 329 PM CDT Mon Jul 2 2018
Afternoon radar and visible satellite observations show lingering
shower activity across the southern River Valley has created a
weak cold pool along the I-94 corridor. This airmass is
characterized by temperatures in the low 70s and dewpoints in the
low 60s, and differentiates a more dry airmass to the north across
eastern North Dakota/northwest Minnesota and a less stable airmass
further south across the tri-state area. Afternoon RAP analysis
additionally show differing air masses with MLCAPE values 500 -
1500 J/kg building across SD/west MN under a strong cap. This
suggests that the more likely area for convective initiation later
today will be focused further south across northeast SD along a
surface warm front evident in afternoon surface obs. With a shear
environment of around 55 knots of effective bulk shear organized
convection is possible in this area.
Recent CAMS show this convection beginning in the 23-01 UTC time
frame and propagating east/northeastward along the southwest
border of the forecast area (roughly from the Wadena to Park
Rapids area). Backed winds at the surface in response to a
deepening surface low to the west along with strengthening mid
level winds due to the nocturnal LLJ may allow low level ESRH
supportive of a tornado threat, though this might be limited by a
multicell storm mode. Hail and strong winds remain the greatest
threat. Finally, some CAMS suggest storms developing along I-94
further west and propagating into the Valley City/Fargo area later
tonight, though the influence of the more stable airmass
currently in place over this region may reduce the chance for
severe storms.
Convection beginning in Montana this evening is expected to
propagate east/northeastward during the overnight hours into
eastern ND/northwest MN through the morning hours. Clearing
conditions mid day Tuesday may allow for enough
insolation/destabilization to allow for a few afternoon
thunderstorms across northwest MN Tuesday afternoon.
.LONG TERM...(Tuesday night through Monday)
Issued at 329 PM CDT Mon Jul 2 2018
An active weather pattern through Wednesday night will bring
continued chances for showers and thunderstorms, with a quiet period
from Thursday to Saturday night.
On Tuesday evening, thunderstorms look likely to develop both along
1) the cold front draped along the MT/ND border and 2) along a sfc
front draped from north central MN into western SD. Despite
lingering showers and storms during the day and mid level capping
Tuesday afternoon, there is potential for some discrete cells or
clusters of storms initiating in areas south of Highway 2 Tuesday
afternoon and evening, as moderate to strong surface based
instability and favorable shear develop amidst high temperatures in
the 90s and dew points in the lower 70s. Additionally most models
suggest this activity and/or other activity developing in the
remainder of Dakotas would likely merge into a complex or cluster of
storms Tuesday night along the nose of the low level jet, as surface
low and an upper shortwave push east across the Dakotas.
With this potent setup, the threat for severe weather will persist
Tuesday night into Wednesday, as any remaining complex or cluster
pushes through eastern ND into northern MN. Large hail to 1.5
inches, damaging winds to 60 mph, and a tornado or two are all
possible threats with severe storms. In addition, an unusually moist
environment sets up Tuesday night and Wednesday with precipitable
water values in the 1.5 to 2.5 inch range and in the 95th to 99th
percentile range of NAEFS climatology. This will yield a notable
threat for heavy rain and perhaps flash flooding, particularly with
the overnight thunderstorms.
For Independence Day, additional shower and thunderstorm activity
will remain possible through the day as the aforementioned complex
pushes out of the area and the cold front remains in the region.
Thus rain chances are most likely to impact any morning or mid day
activities as activity gradually exits eastward along and ahead of
the front. Rain chances are expected to exit the immediate Red River
Valley by Wednesday evening, with remaining shower or storm activity
moving out of the northwest quarter of MN Wednesday evening.
For Thursday through Saturday, a quiet weather pattern sets up with
high pressure and ridging aloft. High temperatures will still remain
in the upper 70s to near 90 degrees during this timeframe, but some
relief from humidity will be felt under a drier airmass.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 646 PM CDT Mon Jul 2 2018
Scattered thunderstorms possible across the area and could impact any
TAF site during the next 24 hours though to uncertain to add to
TAF for a specific time.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JK
SHORT TERM...AM
LONG TERM...BP
AVIATION...JK
Area Forecast Discussion
National Weather Service Green Bay WI
1038 PM CDT Mon Jul 2 2018
Updated aviation portion for 06Z TAF issuance
.SYNOPSIS...
Issued at 223 PM CDT Mon Jul 2 2018
Very warm and increasingly humid again the next few days. There is
a chance of thunderstorms Wednesday into Thursday. The greatest
chance is Wednesday night, though for most of the area they will
probably hold off until after the Fourth of July fireworks
displays have finished.
A pretty typical mid-summer upper pattern is expected during the
forecast period. The main belt of westerlies will remain primarily
across Canada and the far northern United States while the
subtropical ridge covers the central and southern CONUS. The
forecast area will remain near the southern edge of the
westerlies, with flow shifting between southwesterly and
northwesterly in response to the progression of major shortwaves
through the main belt of westerlies.
The upper flow will back southwest the next couple days, allowing
very warm and increasingly humid air to once again overspread the
area. A turn to northwest flow is expected late in the week,
which should result in a return to more seasonable temperatures
and lower humidities. Precipitation will depend on the specifics
of how convection develops. The overall pattern seems to favor AOB
normal amounts, though one well placed MCS could certainly
deliver enough rain to push totals above normal for the week.
&&
.SHORT TERM...Tonight and Tuesday
Issued at 223 PM CDT Mon Jul 2 2018
The latest RAP analysis and satellite/radar imagery show
yesterday`s cold front stretching from the eastern Great Lakes to
near St Louis early this afternoon. Farther north, a mid-level
convergence axis extends from the ND/SD border to northern WI. Cu
has develop in vicinity of this convergence early this afternoon,
with additional mid-level clouds pushing in from the west. A few
high resolution models develop some showers and perhaps a storm
from Rhinelander to Wausaukee later today. Not entirely confident
with that scenario, as models also show the convergence zone
getting pushed north as mid-level heights rise across the region.
Will add an isolated shower mention from 5 through about 9 pm.
Otherwise forecast concerns mainly revolve around cloud trends and
temps.
Tonight...Deep convection is expected to remain to the west
tonight over central Minnesota into the Dakotas. Once any spotty
showers dissipate by around mid-evening, mid and high clouds will
be gradually lifting north with the jet stream. Some blow off from
the storms to the west will likely pass over northern WI late
tonight, but should not have much of an impact on temps. With
mostly clear skies over east-central WI, low temps should range
from the low 60s north to mid 60s south.
Tuesday...Mid-level heights will continue to build across the
region as winds back to the south or southeast. Warmer temps will
invade from the west, with stable conditions yielding plenty of
sunshine. Readings will be several degrees warmer over north-
central WI, but fairly steady over the east. Highs will mostly
fall into the middle to upper 80s, though cooler near Lake
Michigan.
.LONG TERM...Tuesday Night Through Monday
Issued at 223 PM CDT Mon Jul 2 2018
The main forecast concerns are determining the extent of the mid-
week heat and humidity, and thunderstorm potential (especially
during the Fourth of July holiday).
Warmer and more humid air from the Plains will continue spreading
back across the area through Independence Day. Temperatures aloft
(850mb) suggest this round of heat will not be as extreme as the
one a few days ago. At this point, do not anticipate the need for
heat-related headlines, though some precautions may be needed by
those outdoors on the Fourth.
Most of the guidance suggests the possibility of isolated
thunderstorms on Independence Day, with a greater chance Wednesday
night. Upper heights remain very high during that time, and the
best forcing will be focused to the northwest of the area. So the
best chance for storms will probably be if a mature MCS develops
to our northwest and then shifts southeast into the area as the
850 mb flow veers overnight. Such a scenario would probably hold
the rain chances off until after most of the Fourth of July
fireworks displays are complete, though the far northwest portion
of the forecast area will be most at risk of having storms arrive
earlier.
Rain chances will continue into Thursday as a cool front crosses
the area. A few days of cooler and drier weather will follow.
The spread among the guidance increases substantially thereafter.
The GFS would suggest the cooler weather will linger for several
days, while the ECMWF suggests a rather quick return to above
normal temperatures.
Overall, the standard extended forecast initialization grids
based on a broad blend of guidance products seemed to adequate,
so few adjustments were necessary.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1038 PM CDT Mon Jul 2 2018
Relatively quiet weather through the taf period. Generally mostly
clear skies and light winds are expected during the TAF period.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......Skowronski
SHORT TERM.....MPC
LONG TERM......Skowronski
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Indianapolis IN
1125 PM EDT Mon Jul 2 2018
.UPDATE...
The Aviation section has been updated below.
&&
.SYNOPSIS...
Issued at 255 PM EDT Mon Jul 2 2018
High pressure over most of the nation east of the Mississippi
will control Indiana weather until Thursday, when a cold front is
forecast to arrive. By late Thursday a second area of high
pressure system should extend from our state to the north plains.
This system will dominate Indiana weather through Monday as it
shifts to the east coast.
&&
.NEAR TERM (Tonight)...
Issued at 255 PM EDT Mon Jul 2 2018
The main issue is rain chances.
Relatively dry air has moved in but storms persist in the south and
the latest HRRR is slow to end them. Slight chance seems good in the
south early tonight, with dry elsewhere. Enough moisture remains
over the area so skies should be partly cloudy as opposed to
clear.
Consensus temperatures look reasonable given dewpoints and
some clouds.
&&
.SHORT TERM (Tuesday through Thursday)...
Issued at 255 PM EDT Mon Jul 2 2018
The main issues are POPS Tuesday and highs Wednesday.
The models agree the remains of a front be over the area Tuesday.
They disagree about how much this will promote convection. A
complicating factor is warm air aloft will make it harder for
storms to fire. The chance POPs from consensus are a reasonable
compromise. Convective clouds should make Tuesday partly to mostly
cloudy.
Tuesday night through Wednesday night should be a little drier and
partly cloudy as a strong ridge builds aloft. A small chance of
storms will continue in very warm humid air. A front should boost
rain chances again Thursday.
Except for Wednesday, consensus temperatures look reasonable
based on the background fields. Wednesday`s highs were raised
above consensus. Strong ridging aloft should boost temperatures
and the latest MOS reflects this. The blend may not have
identified the trend yet.
There is a good chance a heat advisory will be needed Wednesday.
&&
.LONG TERM /Thursday Night through Monday/...
Issued at 244 PM EDT Mon Jul 2 2018
The main theme of the extended will be a well deserved break from
the heat and humidity as a more seasonable airmass expands into
the region.
The deep upper ridge that has served as the key regulating factor
in the hot and humid conditions of late will be in the process of
a retrograde at the beginning of the extended...with the feature
set to park over the Rockies and northern Plains by the weekend. A
sharp upper level wave tracking east from James Bay will force a
suppression of heights and amplification of a trough east of the
Mississippi River which will ultimately enable a cold front to
sweep through the Ohio Valley Thursday night and Friday. The best
threat for rain and storms throughout the period will exist during
this time frame as scattered strong convection impacts the
forecast area.
Once the front clears the area...the stage is set for a superb
weekend for central Indiana as surface high pressure expands
across the area. Skies will be mostly clear through Saturday and
Sunday with seasonable temperatures in the 80s. A predominant NE
flow will pull much drier and less humid air into the region with
the potential for dewpoints to fall all the way back into the 50s.
The departure of the surface high off the Mid Atlantic coast by
late weekend will encourage a return flow into the Ohio Valley off
the Gulf...with humidity levels beginning to creep back up by
early next week. The increased moisture plume will also provide a
return threat for scattered convection by Monday as highs approach
90 degrees.
&&
.AVIATION /Discussion for the 03/06Z TAFs/...
Issued at 1125 PM EDT Mon Jul 2 2018
VFR through the period.
Will have to monitor fog potential overnight mainly at these two
sites where rain was received today, particularly BMG which is a
climatologically fog prone site as it is. Visibilities are holding
for now and extra cloud cover from late evening convection may
keep them from dropping significantly.
VCTS will be carried at all sites from 15Z tomorrow onward as
convective temperatures are reached and a remnant boundary in the
area should provide enough boost for another afternoon of widely
scattered storms. These should dissipate with the loss of heating
around 01Z.
Winds throughout the period will be less than 10KT and frequently
variable.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM...Ryan
AVIATION...Nield
Area Forecast Discussion
National Weather Service Lake Charles LA
1016 PM CDT Mon Jul 2 2018
.UPDATE...Broken line of showers and thunderstorms over the
eastern portion of the forecast area continues to advance west
southwest. Activity has spiked along well defined outflow from
earlier convection. SBCAPE generally running a respectable
2500-3000 J/KG across this area. This along with enhanced low
level convergence sufficient for maintaining convection. Seeing
some impressive amounts of lightning with a few of the storms.
Special Weather Statements being issued for these. Have bumped up
pops over the area while expanding further westward overnight rain
chances.
&&
.PREV DISCUSSION... /issued 707 PM CDT Mon Jul 2 2018/
DISCUSSION...
For 00z TAF issuance.
AVIATION...
Will have to watch the initial band of convection associated with
tropical wave to our east which is set to approach the Acadiana
terminals over the next hour or so. TAFs were written with just
rain/shower mentions as IR imagery indicated warming cloud tops
and HRRR suggested a quick weakening trend...however as soon as
the forecasts were issued, convection quickly blew up. Otherwise
no significant changes to previous TAF thinking with tomorrow
looking like a relative washout as the wave moves farther wwd and
interacts with deep tropical moisture in place across the region.
25
PREV DISCUSSION... /issued 354 PM CDT Mon Jul 2 2018/
DISCUSSION...A ridge of weak high pressure at the surface is
located over Louisiana, however the ridge extends northeast into
the Appalachians and into the mid Atlantic. An inverted trough is
over the north central gulf south of Mobile which is being driven
west by the ridge to the north. Aloft a ridge is over Texas
keeping SE TX and West LA dry currently.
Through tonight the ridge will continue to push the inverted
trough west toward SE Louisiana. With the incoming moisture from
the trough and the erosion of the local ridge, rain chances will
increase from east to west tonight through Tuesday. The 4th looks
wet with scattered to widespread areas of rain and thunderstorms,
however convection may decrease through the afternoon with the
loss of daytime heating leaving most areas drier post sunset. So
the afternoon BBQ may be a bit wet, however fireworks may not be.
High rain chances will remain in place through Thursday as the
disturbance passes.
Through the event 2 to 4 inches will be common with localized
areas areas near double that, especially near and south of I-10.
Rain fall rates may be intense at times with the tropical airmass
leaving roadways receiving runoff/ponding rather quickly.
A little lull in convection may occur late in the week, however
another inverted trough and upper low will move from the Atlantic
and across the northern gulf again. Higher rain chances are
expected again this weekend.
MARINE...While generally light to moderate flow is expected,
winds and seas may be elevated near scattered to numerous
thunderstorms. The inverted trough will push through the area late
Tuesday/early Wednesday with a slight increase in the onshore
flow.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 73 88 72 88 / 30 70 60 60
LCH 75 89 73 85 / 20 70 70 80
LFT 76 86 74 87 / 50 80 60 70
BPT 76 89 74 84 / 10 60 80 80
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
PUBLIC...23
Area Forecast Discussion
National Weather Service New Orleans LA
1033 PM CDT Mon Jul 2 2018
.UPDATE...
Took thunder out of more interior sections for remainder of
tonight but returned thunderstorms into coastal MS and eastern LA
generally after 3 am with renewed convection around low pressure
circulation. RAP and HRRR showing warm core thicknesses to the
east of the low center which favors nocturnal marine developments
in the pre-dawn hours. No other changes at this time. 24/RR
&&
.AVIATION...
Complex situation in timing onset and duration of convection over
the area, but periods of thunderstorms expected for a large
portion of the valid TAF period. VFR ceilings outside convection
lowering to MVFR levels in heavy downpours with visibility briefly
in IFR ranges. Gust potential 25-40 kt in wet microbursts. 24/RR
&&
.PREV DISCUSSION... /issued 401 PM CDT Mon Jul 2 2018/
SHORT TERM...
Overall, the forecast isn`t much different from previous. A broad
trough of low pressure is currently located across the central Gulf
Coast just east of the CWA. On radar, the rotation of the low is
quite obvious although isn`t a closed low at this time. When
experiencing tropical air masses such as this one, the available
moisture is typically much higher than normal and brings the
potential for widespread heavy rainfall. This morning`s sounding
showed PW around 2 inches. GFSbfr soundings show this number
creeping up about 20% tonight into Tuesday. That will put the PW
well above the 90th percentile and possibly close to the average
max for this time of year. Compared to other previous easterly
waves, this one is on the average to below average range (example:
PW was around 2.8" in 2016 BR metro flood event compared to 2.4"
with the current one). For the rest of this afternoon, there`s
still enough dry air aloft in the 850mb to 500mb level for some
storms to produce strong downbursts. As high as 50mph has been
recorded already this afternoon.
As time progresses tonight into Tuesday, the broad low will move
into and across the CWA. Model soundings show the column saturating,
alleviating most of the downburst potential. On the other end of the
spectrum, this will increase the threat for heavier rain and
increased rainfall coverage. Therefore, have increased POPS into the
80 to 100% range. Still have Flash Flood Watch in thoughts, but will
continue to pass on issuing one. Event duration will be
relatively short and flash flood guidance is quite high. In
addition, the bulk heavier rainfall will most likely be a less
prone flash flood region of the CWA, south of I-10.
LONG TERM...
The rest of this week will be characterized by increased rain
chances even in the wake of the first easterly wave as another
(weaker) one follows in its footsteps Thursday and Friday. Over the
weekend, models actually show a frontal boundary approaching the
area from the northeast as an upper trough swings across the
northeast CONUS. The boundary will wash out as it gets here and aide
in maintaining higher rain chances .
MEFFER
AVIATION...
VFR conditions area giving way to MVFR/IFR as scattered to numerous
showers and storms progress from west to east across the region.
Some of these storms have been producing gusts over 40kts. The bulk
of peak impact will most likely be from 09z through 21z Tuesday as a
broad low pressure passes across the area. Periods of heavy rainfall
will be likely with short durations of of VLIFR visibilities at
times.
MEFFER
MARINE...
A weak area of surface low pressure currently over the offshore Gulf
waters south of Alabama is expected to move west into the coastal
marine zones between Pascagoula and Southwest Pass tonight. Winds
will respond in direction, starting out northerly to westerly, then
becoming southerly and easterly on the eastern side of the low as it
moves west across the forecast area. Winds speeds are expected to
remain mostly around 10 knots or less through tonight. As the low
moves west across the remaining marine zones Tuesday, southerly
winds on the east side could rise as high as around 15 knots over
the eastern waters, but then the wind speeds should ease back to
around 10 knots or less by late Tuesday night as the low moves
towards the upper Texas coast. Wind speeds are expected to then
remain fairly light the remainder of the week due to weak high
pressure. Wave heights are expected to be mostly 1 to 2 feet today
through Wednesday morning, except for some 3 footers over some
southeastern waters today and tonight and eastern waters Tuesday.
Waves should then lower to around 1 foot from around midday
Wednesday through Friday night. Areas of scattered to numerous
thunderstorms can be expected across the marine area through
Tuesday, so expect periodic higher winds and waves. After Tuesday,
the more typical isolated to at times scattered coverage of showers
and thunderstorms can be expected. 22/TD
DECISION SUPPORT...
DSS code: Blue.
Deployed: none.
Activation: none.
Activities: Monitoring excessive rainfall potential through Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 75 84 75 88 / 60 80 20 50
BTR 76 85 75 89 / 70 80 30 60
ASD 77 85 77 88 / 70 60 20 60
MSY 78 84 79 88 / 70 70 20 60
GPT 77 85 79 88 / 70 60 20 50
PQL 77 86 77 88 / 70 70 20 50
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Blacksburg VA
914 PM EDT Mon Jul 2 2018
.SYNOPSIS...
High pressure across the region will maintain ongoing hot and
humid conditions into Tuesday, with more limited thunderstorm
coverage than today. Somewhat cooler but still quite warm and
humid conditions will continue through Thursday, with an
increase in shower and thunderstorm chances late in the week
into the weekend as a cold front passes through from the
northwest.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 911 PM EDT Monday...
Band of convection along the earlier western mountain
convergence zone has pushed west of the region this evening
leaving mainly debris clouds west and residual spotty light
rain across SE West Va. Latest short term guidance continues to
unfold the convection farther off to the west through midnight
leaving only mid clouds mountains and mainly clear out east.
Still cant rule out an isolated shower developing over the next
few hours mainly west, but given worked over western
instability per analysis, appears the dry HRRR is on track for
little added shower coverage overnight. Thus keeping things dry
for the most part with some added fog in the valleys. Think a
bit more widespread fog coverage possible in spots that saw
earlier heavy rainfall, espcly SE West Va. into parts of the New
and Roanoke valley regions once any mid cloud canopy fades.
Temps still quite warm/muggy espcly where missed out on cooling
showers, so keeping lows mainly low/mid 70s from Roanoke east
and 65-70 west.
Update as of 755 PM EDT Monday...
Quick update to let the going heat advisory for Buckingham
county expire this evening and to adjust pops with most
convection now shifting farther to the northwest. Heat advisory
resumes for the same area Tuesday afternoon with even hotter
temperatures expected.
Previous discussion as of 330 PM EDT Monday...
The forecast area remains under influence of an anomalous
594-dm ridge associated with elevated heat and humidity levels
centered over southern New York State. A subtropical low located
south of Bermuda is forecast to undercut the southern end of
the ridge tomorrow, leading to a little greater easterly
component to surface winds as it nears the coastal Carolinas.
The heat will continue to be the main story for most locations. The
Heat Advisory remains in effect until 8 PM Monday for Buckingham
County. However, with the afternoon package, a Heat Advisory has
been issued for tomorrow (Tuesday) for Buckingham County again as
well from noon to 8 PM. Per collaboration with LWX and AKQ, we
agreed to keep the Heat Advisory for the daylight hours - leading to
the double Heat Advisory headline. Confidence was highest in heat
index values of around 105 degrees being reached in Buckingham
County; further expansion potentially into the central VA Piedmont
(away from Smith Mountain Lake) may be needed later but will let
later shifts determine if that is warranted.
A few thunderstorms have developed this afternoon in an elongated
zone of weak confluence which trails from the Blue Ridge northward
into central NY. Air mass remains moderately unstable in this zone,
though even greater instability values reside further east where
little forcing for ascent is noted and convective depth is more
shallow. Thunderstorms should continue in scattered coverage through
sunset mainly along and northwest of the Blue Ridge; a few may
become strong and wouldn`t entirely discount one pulse storm that
may briefly reach severe limits but sub-severe thunderstorms should
characterize the convective threat today. Gusty winds, small hail
less than an inch in diameter, torrential rain and frequent CG
lightning would be the main hazards in thunderstorms. With lack of
any deeper triggering mechanism and as reflected in latest
convection-permitting solutions, thunderstorm coverage and strength
will begin to wane with loss of sunset around 8 PM, with convection
ending by late evening. Should see a mostly clear to partly cloudy
evening (convective debris mid clouds predominantly). With ample
moisture, the potential for patchy mist or light ground fog west of
the Blue Ridge will exist, as well as in the Piedmont of VA and NC.
Areas that saw rain today will have a greater chance. Though heat
indices will fall this evening, it will remain a muggy night with
little significant relief from heat with lows well into the 60s. Mid
70s will be rather common east of the Blue Ridge into the foothills
and Piedmont areas.
Mid-level ridge axis should still remain in place, though its
southern extent will tend to weaken somewhat later in the day. After
any fog burns off, we`ll be looking at a continued very warm and
humid day across the region. 850 mb temperatures are progged by the
GFS and NAM to be around +20 to +24C. Low to mid 90s should be
common, except upper 80s in southeast West Virginia. Dewpoints
should range from the upper 60s to lower 70s in most areas except
for Buckingham County where mid-70s dewpoints are forecast. Given
higher dewpoints in Buckingham County and with temps into the mid
90s, felt confident enough to issue another heat advisory with this
package for Tuesday for Buckingham County. Forecast heat index
values elsewhere in the Piedmont/Southside range between 102-104F;
wasn`t confident enough as yet given forecast heat index values on
extending the heat advisory further southwest into the Lynchburg
metro area counties and into Pittsylvania County. Further expansion
may be needed it becomes more likely that even warmer heat index
values are expected. Thunderstorm threat tomorrow looks limited;
though the increase in east flow should allow for some local
convergence to spark showers and thunderstorms mainly along the
southern Blue Ridge (PoPs 20-30%) versus in the Alleghany Highlands
(PoPs 15-20%).
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 300 PM EDT Monday...
A sprawling upper level ridge over the much of the eastern 2/3rds of
the country Wednesday morning retrogrades west, allowing a weakness
to form in the upper levels by Thursday afternoon.
Well above normal temperatures will continue, but heat index values
east of the Blue Ridge remain below advisory criteria with highest
values near 100 in the VA Piedmont for both Wednesday and Thursday.
Expect to see slightly higher coverage in precipitation on
Wednesday, as forecast sounding show mid-level cap weakening, while
a moist weak upslope southeast low-level flow will also help to
generate shower and storms. In addition, PWAT values will be on the
rise thanks to moisture spreading west on extreme northern edge of a
west moving upper level low across the northern Gulf.
Scattered shower and storms continue Thursday with lowering heights
and continued mid-level cooling, but as winds veer in advance of the
approaching northern stream system, we lose the upslope component
for areas along and east of the Blue Ridge. Therefore, kept POPS at
slight chance to change range.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 300 PM EDT Monday...
The long-range deterministic models are in good agreement with
deepening and upper level trof across the eastern U.S. which will
help push a cold front through our area Friday night or Saturday,
with the ECMWF slightly slower than the Canadian and GFS solutions.
The GFS has shown better run to run consistency with the timing of
this frontal passage, and with the ECMWF trending more amplified
with the upper trof, leaned toward the faster solutions.
The upper trof is reinforced briefly on Sunday with another northern
stream wave digging southeast. The 12Z GFS has come into better
agreement with other models with a more progressive solution
with this second wave.
With PWAT values from the 12Z GEFS 1-3 standard deviations above
average on Friday in advance of the front, locally heavy rains will
be possible and kept POPs in the high chance to likely category
during this time. Confidence is slightly higher than the front will
push through our forecast area keeping only a small chance for POPs
Saturday night into Sunday in case ECMWF verifies.
Otherwise, temps will continue to be above normal in advance of the
frontal passage, and if cloud cover is less than expected Friday,
temps could exceed current forecast with downsloping winds with
nose of 850mb thermal trof entering our region.
Continued the trend of lowering temps/dew points Saturday into
Monday, with signals increasing for below normal temps Sunday and
Monday.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
As of 700 PM Monday...
Complex of deeper convection along a residual outflow boundary
continues to pass north and west of KBLF/KLWB with showers
expected to exit these areas by sunset. Other isolated showers
may also pop up across the region during the next hour or two
before loss of heating but not enough coverage to include
mention. Otherwise looking at mainly VFR across the region for
a while into early tonight once any convection fades.
High dewpoints and any wet ground from showers/thunder in
western terminals should lead to overnight/early morning
development of patchy fog. Kept in BR mention at Danville,
Blacksburg and Lewisburg with vsbys 2-4SM; confidence is low on
how low vsbys may get. Winds light and variable (outside any
thunderstorms).
VFR to return again on Tuesday with likely less cumulus around
than Monday given dry air aloft. May see isolated thunderstorm
development along the southern Blue Ridge and across the far
northwest Tuesday afternoon but likely to see less convective
coverage overall than today. Winds light and variable then
becoming easterly/southeasterly around 5-10 kts.
Extended Aviation Forecast...
VFR conditions will be the primary flight category through at
least mid-week, though with late night-early morning fog, and a
chance of an afternoon thunderstorms each day, mainly in the
mountains. A frontal system approaches from the northwest late
in the week which should allow somewhat better coverage of
showers and storms on Friday. Any overnight fog will depend on
where it rains and the degree any overnight clearing can take
place. Expecting drier air under high pressure building in from
the north to bring VFR conditions to start the weekend.
Confidence in the above forecast is high through mid week and
then moderate for late in the week.
&&
.CLIMATE...
The following are current record highs for the the primary
climate sites within the RNK CWA.
Tuesday 07/03/2018
Site MaxT Year HiMin Year
KBLF 89 2012 72 1998
KDAN 99 1968 74 2014
KLYH 97 2012 74 1903
KROA 97 2012 75 1980
KRNK 95 1954 67 1963
&&
.EQUIPMENT...
As of 700 AM EDT Saturday...
The NOAA weather radio transmitter in Hinton, West Virginia
that is WXM72 and broadcasting at a frequency of 162.425 MHz
remains off the air, and will likely remain so through the week
Parts are on order to repair the transmitter, but there is no
known time of restoration. We apologize for any inconvenience.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Heat Advisory from noon to 8 PM EDT Tuesday for VAZ047.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AL/JH
NEAR TERM...AL/JH
SHORT TERM...PH
LONG TERM...PH
AVIATION...AL/JH/JR
CLIMATE...RAB
EQUIPMENT...WERT