Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/24/17
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
533 PM MDT Fri Jun 23 2017
.AVIATION...
00Z TAF CYCLE
The backdoor cold front has moved through KSAF, but has temporarily
stalled east of KABQ and is forecast to push through at 01Z then
through KAEG at 02Z. An airport weather warning is in effect at KABQ,
where east canyon/gap winds will gusts to +40kts this evening and
overnight. Convection is diminishing rapidly and will not impact area
terminals this evening. MVFR cigs are forecast to develop overnight
at KLVS, then later Saturday morning at KTCC and KROW. A round of
storms is forecast to develop along the Continental Divide Saturday
afternoon and move southeast toward the Rio Grande Valley, possibly
impacting KAEG, KABQ and KSAF going into the evening hours.
11
&&
.PREV DISCUSSION...310 PM MDT Fri Jun 23 2017...
.SYNOPSIS...
A cold front has pushed through the eastern plains today, which
dropped the temperatures considerably. The front will push through
the gaps of the central mountain chain late this afternoon and
evening. Strong and gusty winds are expected below canyons in the Rio
Grande Valley. The front will continue to race westward overnight.
Moisture behind the front will set the stage for an active weekend
with showers and thunderstorms. Some storms may be strong or severe
with hail and gusty winds. The active weather will continue into
Monday, then drier air should arrive for mid week.
&&
.DISCUSSION...
The back door cold front has backed up to the central mountain chain
this afternoon, and soon, will push through the gaps and into the
Rio Grande Valley. Looks like the easterly winds will initially be
lighter, but will ramp up quickly this evening and persist into the
overnight. Considered moving up the Wind Advisory to start at 4pm or
so, but the strongest winds should be after 6pm, so will leave as
is. The front will quickly shift westward, nearing the AZ border
around midnight. A few storms are developing along the central
mountain chain this afternoon, but so far are struggling to become
very strong. HRRR indicates they won`t make it too far off the high
terrain this evening.
Thanks to the front, the streak of heat advisories should come to an
end. Dewpoints behind the front have increased into the upper 40s
and 50s behind the front and this moisture, though perhaps not as
rich, should make it across much of western NM tonight. The moisture
will mix out on Saturday across far west central and northwest NM,
but elsewhere, will set the stage for a much more active
thunderstorm day. Areas between the ContDvd and the central mountain
chain look to be favored during the daytime period, with a few
strong or severe storms possible. Steering flow may take the storms
across the plains Saturday night. Stormy weather will continue into
Sunday and Monday. Both days look quite active with the potential
for strong to severe storms. Fortunately though, the cloud cover and
precipitation will keep it cooler, especially across the plains.
Below normal temperatures are expected for areas along and east of
the RGV. Still warm across the west, but only 3 to 7 degrees above
normal, as opposed to 8 to 14 like the last few days.
Stronger westerlies look to return Tuesday and Wednesday across
northern NM with a corresponding dry slot moving across the area.
This dry air should mix down and subsequently start to limit
thunderstorm chances, first across the north, and with time across
the south.
34
&&
.FIRE WEATHER...
The backdoor front raced south and west across the eastern plains
and seeped into the Rio Grande Valley overnight and this morning.
The low level moisture has mixed out of the RGV for the most part
this afternoon, but the east/southeast gap winds will return later
this afternoon and will be roaring after 6pm in ABQ. Gusts up to 50
and maybe 55 mph between 7pm and 3am through and below the canyons,
especially Tijeras and Bear Canyons. Despite the sharp increase in
low level moisture convection will be pretty limited this evening
and overnight, pretty much confined to the east slopes of the
central mountains and eastern highlands, and across Chaves County.
RH recoveries will be be much better tonight, fair to good in the
west and excellent in the east. The front will reach the Continental
Divide early Saturday morning and probably spill west to the AZ
border.
This will produce an active weekend with widespread showers and
thunderstorms and mostly below normal high temperatures. Mixing
heights will lower and vent rates will crater in the east this
weekend but not so much in the west.
Pretty much status quo for Monday then a drying and warming trend
still looks to take place for the rest of next week, with less
coverage of storms Tuesday and Wednesday, and dry Thursday and
Friday. A couple of back door cold fronts next weekend could lead
to a return of more moisture and cooler temperatures.
CHJ
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM MDT this evening for the following zones...
NMZ505>509-519-520.
Wind Advisory until 2 AM MDT Saturday for the following zones...
NMZ519.
&&
$$
34
Area Forecast Discussion
National Weather Service Albany NY
1042 PM EDT Fri Jun 23 2017
.SYNOPSIS...
Warm and humid air mass will continue into tonight ahead of a
cold front, along with occasional showers and thunderstorms,
some of which could produce locally heavy rainfall. Saturday
will see a drying trend behind a cold frontal passage.
Seasonable temperatures return on Sunday, with perhaps a few
passing showers or a thunderstorm over mainly northern portions
of the forecast area.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 1042 PM EDT...A cold front continues to slowly move
eastward from the eastern Great Lakes and southeast Ontario into
western and northern NY this evening. It has taken time, but
shower and isolated thunderstorm coverage has begun to increase
across the forecast area, especially the eastern Catskills,
Adirondacks, and Lake George Region. The convection that formed
across eastern PA and NJ weakened and missed most of the
forecast area early this evening, but some showers are popping
up over the mid-Hudson Valley.
The latest SPC RAP Mesoanalysis continues to show
MLCAPE/SBCAPEs of 500 J/kg or greater south and east of the
Capital Region. PWATs have risen into the 1.8-2.0+ inch range.
The 00Z KALY sounding has a PWAT of 1.91" and KOKX 2.04". Heavy
rain looks to be the bigger threat the rest of the night, as
the right entrance region of an H250 jet streak moves over
portions of the forecast area. We tempered the area of the
Marginal Risk down in the HWO from the Capital Region south, but
the weak lapse rates aloft with the waning instability should
suppress any severe threat. Most the forecast area has had
limited rainfall, but the showers will be capable of at least
0.50"/hr hourly rates. The 3-km HRRR has continued to show heavy
rain over the region, but has been off with the placement of
the heavy rain the past several runs. Areas of urban/poor
drainage flooding are still possible, but unless a heavier band
moves north the threat for an isolated flash flood has begun to
diminish, though locations south of the Capital Region into the
mid-Hudson Valley into NW CT could get a quick inch or two
through daybreak with the front moving through. We have retooled
the pops considerably with this update and have kept chance or
likely pops in with the front moving through 06Z-12Z.
It will remain warm and humid, with lows mainly in the mid 60s
to lower 70s. Dewpts will remain in the 60s to lower 70s until
the front moves through from northwest to southeast between
06Z-12Z.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
Saturday, the aforementioned strong shortwave will be crossing
through the region during the morning hours. Rain and/or showers
will likely persist well into the mid morning hours from the
Albany/Saratoga/Lake George region and points south and east.
Some locally heavy rain will be possible, especially from the
mid Hudson Valley northeast into NW CT and possibly the southern
Berkshires. The rain should finally moves S/E of the region by
early afternoon, with clearing expected. However, another upper
level impulse could trigger isolated showers to develop later in
the afternoon, especially across the eastern Catskills. It will
become quite breezy by Saturday afternoon, with wind gusts
possibly reaching 25-30 mph. Afternoon highs should reach the
mid 70s to around 80, except 60s to lower 70s across some higher
elevations of the southern Adirondacks and southern VT, with
some lower/mid 80s possible across portions of the mid Hudson
Valley where afternoon sunshine and a downsloping flow may
enhance warming.
Saturday night, generally clear to partly cloudy and cooler,
with lows in the 50s to lower 60s.
Sunday, a strong upper level disturbance is expected to approach
in the afternoon. It appears that the best forcing and
associated shallow instability will be mainly across northern
areas, north of I-90. Expect scattered showers and isolated
thunderstorms to develop by afternoon in these areas. With
strong winds anomalously cold air aloft, some gusty winds and
small hail could occur in any deeper convective elements. Highs
should mainly reach 75-80 in valley areas, with 60s to lower 70s
across higher terrain.
Sunday night, any evening isolated/scattered convection should
decrease in the evening hours, although could persist across the
southern Adirondacks well into the night which will be in
closer proximity to the main upper level forcing. Otherwise, it
should be cool, with lows mainly in the 50s.
Monday-Monday night, another fast moving disturbance may trigger
isolated to scattered showers/storms Monday afternoon/evening.
Again, with fairly strong winds and cold air aloft, some small
hail/gusty winds could occur with any deeper convective
elements, despite fairly isolated/scattered coverage. Highs
should reach the 60s and 70s, with lows mainly in the 50s,
except for some 40s across portions of the southern
Adirondacks/southern VT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The extended period begins with a shortwave trough from the Corn
Belt states digging eastward into the Northeast. For the morning
hours, included slight chance POPS for the lower half of the CWA and
chance POPs for the upper half due to southwest flow aloft and PVA.
Increased POPS for the afternoon as guidance is in agreement that
the trough axis passes through during this time. While daytime highs
will be about 5 - 10 degrees below normal only in the upper 60s/low
70s, included thunderstorm potential due to cool pool aloft, daytime
heating that could lead to some instability (200 - 800 J/kg modeled
CAPE) and impressive upper level dynamics (100-110knots 300mb jet
over New England).
The trough should exit from west to east Tuesday night with cool
Canadian air filtering into the region behind it. In fact, as skies
clear overnight and winds stay light, radiational cooling should
allow overnight lows Tuesday night to tumble into the low 50s for
the majority of the CWA and even into the 40s in the Adirondacks
(again about 5 - 10 degrees below normal).
Ridging tries to build in from the southwest on Wednesday as high
pressure noses in from the Tennessee Valley but the high`s center
should stay well to our south as strong westerly winds within zonal
flow aloft quickly return over the Northeast. Either way, we should
stay mainly dry on Wednesday with highs warming back into the mid
upper 70s. The next system looks to be in the Great Lakes/southern
Canadian Thursday/Friday with its associated warm front
potentially reaching our region. Given this is nearly a week
away, it`s no surprise models differ on timing but the Euro and
GFS both suggest the warm front could stall somewhere in our
northern CWA, presenting us with multiple forecast challenges.
Thus did not differ much from the Super Blend for this period.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
A cold front will slowly approach from the west tonight with
showers and isolated thunderstorms ahead of it with MVFR/IFR
conditions for KGFL/KALB/KPOU/KPSF. The front will move south
and east of the region Saturday morning with an improvement to
VFR conditions, as a drier air mass builds in.
Showers and thunderstorms will increase across eastern NY and
western New England between 00Z-04Z from the south/southwest to
the north/northeast. The best chance of a thunderstorm will be
for KPOU/KPSF and a TEMPO group was used to highlight this
potential. Less instability is further north and thunderstorms
have been left out of the KALB/KGFL TAFS. Showers will become
widespread before midnight, and continue until 12Z-15Z from KALB
north and west, and then diminish in the wake of the front for
KPSF/KPOU between 15Z-18Z. Cigs/vsbys will lower to MVFR/IFR
conditions in the showers/isolated thunderstorms overnight. The
best chance of sustained IFR cigs/vsbys will be for KPOU/KPSF
between 07Z-15Z with possibly some brief LIFR cigs at KPSF. A
return to VFR conditions is expected by the late morning into
the afternoon from northwest to southeast for the terminals.
Few-scattered cumulus and/or sct-bkn cirrus may linger in the
afternoon, especially south and east of KALB.
The winds will be from the south to southwest at 5-10 kts
tonight with stronger winds possible with any thunderstorms.
The winds will shift to west to northwest between 11Z-14Z at
7-12 kts, and increase to 10-15 kts by the late morning and
early afternoon with some gusts in the 20-25 kt range especially
at KALB/KPSF.
Outlook...
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Moderate Operational Impact. Scattered SHRA...TSRA.
Sunday Night: Low Operational Impact. Isolated SHRA.
Monday: Moderate Operational Impact. Scattered SHRA...TSRA.
Monday Night: Low Operational Impact. Isolated SHRA.
Tuesday: Moderate Operational Impact. Chance of SHRA...TSRA.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
Wind gusts of 25-30 mph possible Saturday afternoon...
Warm and humid weather will continue into tonight, along with
periodic showers and thunderstorms, some of which could produce
locally heavy rainfall. Saturday will see a drying trend behind
a cold frontal passage. Seasonable temperatures return on
Sunday, with perhaps a few passing showers or a thunderstorm
over mainly northern portions of the forecast area.
RH values are expected to rise to 90-100 percent tonight, then
fall to 40-50 percent Saturday afternoon.
South to southwest winds this evening of 5-15 mph should shift
into the west toward daybreak at similar speeds. On Saturday,
winds will become west to northwest at 10-20 mph with some gusts
of 25-30 mph possible.
Winds will be stronger, and variable in direction in and near
any thunderstorms.
&&
.HYDROLOGY...
Showers and thunderstorms will become more widespread later
tonight as a frontal system gradually moves across the area. It
will become more humid, so there is the potential for locally
heavy rainfall. Some urban/poor drainage flooding and isolated
flash flooding will be possible. Basin average rainfall
forecast to be around a half to three quarters of an inch, but
locally higher amounts will occur in thunderstorms. Showers and
thunderstorms with locally heavy downpours may linger into
Saturday morning from the Capital Region and points south and
east.
Mainly dry weather then expected for Saturday afternoon with
isolated to scattered showers and thunderstorms possible Sunday
into Monday.
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.
&&
.EQUIPMENT...
KGFL airport observations are coming in and we will continue to
monitor this trend.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...KL/Wasula
NEAR TERM...KL/Wasula
SHORT TERM...KL/Thompson
LONG TERM...Speciale
AVIATION...Wasula
FIRE WEATHER...KL/Thompson
HYDROLOGY...KL/Thompson
EQUIPMENT...WFO ALY
Area Forecast Discussion
National Weather Service Columbia SC
1041 PM EDT Fri Jun 23 2017
.SYNOPSIS...
High pressure extending into the forecast area from the Atlantic
will weaken tonight ahead of an approaching cold front. The
slow moving front will be in the area Saturday through Monday.
Numerous showers and thunderstorms are expected along and ahead
of the front. Unseasonable drier weather expected by the middle
of next week.
&&
.NEAR TERM /UNTIL 8 AM SATURDAY MORNING/...
Showers and thunderstorms struggled to develop this afternoon
with most of the activity along the coast and a few showers
making the eastern Midlands. Cold front continues marching
toward the forecast area...currently stretched from
northwestern GA through central AL. Expect clouds to increase
overnight as the front nears the area and pwat values surge to
over 2 inches around daybreak. With the clouds overnight lows
will remain on the warm side with most locations in the mid to
upper 70s.
&&
.SHORT TERM /8 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
A cold front will sag southward through central South Carolina and
east central Georgia on Saturday. PW values in excess of two
inches and 850mb winds speeds 20-30 knots parallel to the
frontal boundary should lead to localized flash flooding,
especially along and south of I-20. WPC has that area in a
Slight Risk for flooding.
The frontal boundary pushes to the coast during Saturday Night into
Sunday. There should be sufficient residual PW behind the front for
scattered diurnal convection, especially south and east of Columbia.
Much drier and cooler air filters into the region Sunday Night into
Monday with highs only in the lower to mid 80s and dewpoints in the
50s to lower 60s. There may be some convection in the far south
related to the sea breeze front.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
An unseasonably cool and dry airmass will dominate through much of
next week with highs in the lower to mid 80s and lows in the upper
50s to mid 60s. Some moisture and warmer temperatures will return on
Thursday and Friday as the surface high moves into the Atlantic
Ocean.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
High confidence for VFR conditions through at least 06Z.
Isolated convection possible overnight given weakly unstable
airmass. Probability too low to include in TAFs at this time.
Southerly winds will be near 10 knots overnight so fog not an
issue.
HRRR guidance and Lamp suggest low threat for stratus...so kept VFR
overnight. Still anticipate an increase in clouds with bases
above 3000 feet during the early morning hours. Could see
scattered showers develop at DNL/AGS by daybreak. More
widespread convection expected to affect the TAF sites by early
afternoon ahead of a slow moving cold front. Strong gusty winds
possible with storms in addition to cig/vsby restrictions.
EXTENDED AVIATION OUTLOOK...Convection and associated restrictions
will be possible Saturday night through Sunday ahead of a cold front.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service State College PA
1154 PM EDT Fri Jun 23 2017
.SYNOPSIS...
The combination of an approaching frontal system and the
remnants of Tropical Storm Cindy will funnel a plume of deep
tropical moisture bringing a steady rain to southern
Pennsylvania tonight. Occasional lighter showers are expected
across the northwest half of the state through the first half of
tonight. The cold front will push east across the region during
the morning Saturday, followed by drier and cooler air with
comfortable humidity that will last through much of next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Showers are becoming more numerous once again as the leading
edge of the deep plume of tropical moisture begins to drift
across southwestern and south-central PA.
Moderate surface and ML instability persists across the Lower
Susq Valley this evening, and a few brief, strong TSRA should
race quickly ENE across that region within the strongly sheared
llvl environment.
Temps are still in the mid to upper 70s across the Lower and
Middle Susq Valley, while reading across the Central, Northern
and Western mtns are in the mid 60s to low 70s.
Analysis shows PWATs exceeding 2" (2-4 sigma) in a wide plume
from the Louisiana Gulf Coast up into central PA, and moisture
transport vectors indicate a continued advection of this
tropical airmass into our region.
After a few to several more tenths of an inch of rainfall across
the Central and Nrn Mtns, with up to an additional 0.50-1.00
inch over the southern tier counties of PA, there could be some
minor flooding problems across the Laurels and southern tier
counties. However, large scale outflow boundary(s) (seen on
satellite animation and regional 88D mosaic) were driving the
stronger/heavier rain producing convection to the south of the
state tonight.
With the steadiest and heaviest tropical rains (and embedded
taller convection) impacting the SW counties of the state attm,
and the Cfront just making its way inland of Lake Erie`s SE
shore, will maintain high pops throughout the first half of
tonight.
The most vulnerable area for heavy to possibly excessive rain
amounts, it looks to be the Laurels where instability will
combine with terrain bringing enhanced lift causing localized
heavier amounts. As a result we will continue the Flash Flood
Watch through 09Z Sat for our SWRN 4 counties.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Conditions will improve rapidly Saturday morning as the deep
moisture speeds eastward. NHC expects whatever is left of Cindy
to be on the MD coast by 8AM so the best of the rain will be
over with drier air sweeping in behind the departing low and
cold front.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Models have trended toward much better agreement with the
evolution of the seasonably strong large scale upper trough over
the Eastern U.S. A couple of shortwave impulses reflecting weak
surface fronts or troughs will provide a limited/mainly diurnal
opportunity for widely scattered showers/isolated low- topped
thunderstorms Sunday-Tuesday. However, much of the this period
will be pleasant and dry with below normal PW supporting low
humidity and below normal temperatures relative to late June
climatology.
The trough is fcst to lift out and leave a more zonal pattern by
the middle of the week, followed by a resurgence of the
Southeast U.S. upper ridge. Models and ensembles show the ridge
breaking down in the west as a trough shifts east across the
Rockies into the Plains. Southerly flow increasing ahead of its
attendant frontal system should result in an upward/warmer trend
in temperatures accompanied by low level moisture/humidity.
Expect max/min temps to get back to seasonal levels around
midweek and likely reaching above normal levels by next Friday.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Wide range of flying conditions continue to prevail across
Central Pennsylvania this evening /04z/. Much better than
previously forecast, with VFR conditions existing at most TAF
locations, with the exception being KBFD.
One last surge of rain and embedded convection will make a run
at southern tier and southeastern counties before rapidly
winding down after 08z/09z time frame. HRRR would lead us to
believe that last of any significant rain will be exiting
eastern portions of Central Pennsylvania around 10z.
Moist low levels and upward flow will likely bring or keep
western airfields under low ceiling restrictions until the
14z time frame, but elsewhere, conditions could be VFR by 10z-
12z.
With rain moving off quickly Saturday morning, a brisk west-
northwest wind and a quick return to VFR conditions is
anticipated.
.OUTLOOK...
Sat...Scattered restrictions in AM showers...otherwise becoming
VFR.
Sun...Mainly VFR.
Mon-Tue...Mainly VFR, but with a chance of SHRA/TSRA.
Wed...VFR.
&&
.EQUIPMENT...
KCCX radar will be offline for approximately 4 days starting
Saturday, June 24th for technicians to install the first of 4
major service-life extension upgrades. The work on the radar has
been scheduled to minimize potential impacts to operations and
will be delayed if hazardous weather is forecast.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 5 AM EDT Saturday for PAZ024-025-033-
034.
&&
$$
SYNOPSIS...La Corte/Lambert
NEAR TERM...La Corte/Lambert
SHORT TERM...La Corte
LONG TERM...Steinbugl
AVIATION...Jung
EQUIPMENT...
Area Forecast Discussion
National Weather Service Duluth MN
937 PM CDT Fri Jun 23 2017
.UPDATE...
Issued at 937 PM CDT Fri Jun 23 2017
Showers continue to percolate over northeast Minnesota, east of
U.S. Highway 53. Another batch of showers was found in northwest
Wisconsin along the St. Croix River valley. Showers were also
occurring over western Lake Superior and trying to move inland.
This activity is in response to an upper level short wave moving
overhead. Made some pop adjustments due to this activity.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 247 PM CDT Fri Jun 23 2017
An upper-level low will dive southeastward from southern Manitoba
tonight across the Northland. An associated mid-level shortwave
trough will accompany this upper-level low, and brush just over our
southwestern counties Saturday morning. The bulk of the positive
vorticity advection will stay to the south and west with this wave.
However, chances of precipitation will be highest over the
International Border region due to a stronger corridor of isentropic
upglide as the mid-level trough passes to the south. Mid-level winds
will be westerly towards the mid-level trough, which should ride
upward over the isobaric surfaces, causing this isentropic lift.
Analysis of the RAP model also indicates a corridor of 950-800 mb
layer FGEN along this band of lift. By Saturday afternoon, showers
and some thunderstorms will expand as the atmosphere becomes more
unstable. Values of MUCAPE vary quite a bit between the guidance, so
confidence in chances of thunderstorms will be low, but cannot rule
them out entirely. Will maintain slight chances of thunderstorms
through Saturday afternoon for most of the region. Severe weather is
not expected, but the strongest storms could be capable of
occasional cloud-to-ground lightning and small hail as 500 mb level
temperatures drop into the 20 to 25 degree below zero range.
Low temperatures tonight will once again be cool as we remain in
this northwesterly, cyclonic flow, as lows approach the upper 40s
and lower 50s across the area, which are just slightly cooler than
seasonal normal. Same story for Saturday with the high temperatures,
as highs remain cooler than normal, with values ranging from the
upper 50s across the Iron Range, and into the lower to mid 60s over
the south.
.LONG TERM...(Saturday night through Friday)
Issued at 247 PM CDT Fri Jun 23 2017
A couple more shortwaves will impact the region Saturday night into
Sunday night in northwest flow aloft then a brief dry period will
occur before chances for showers and storms return mid through late
next week.
A chance for showers and a few thunderstorms will continue into
Saturday evening then another shortwave will dive south into
northern Minnesota late Saturday night. The showers may diminish for
a time Saturday night but will then increase again Saturday night
into Sunday with the wave. The best chance for rain will be on
Sunday and we have showers likely over parts of northeast Minnesota
into northern Wisconsin. A few thunderstorms will also be possible.
Temperatures will remain cool with highs Sunday from the upper
fifties to middle sixties.
A western ridge will slowly move east Sunday through Monday and
bring a dry period starting Monday and continuing into Tuesday. The
upper ridge will be over the region Tuesday with a southerly low
level flow developing. High Monday will be warmer and be from the
upper sixties to around seventy, then warm into the seventies on
Tuesday for most areas.
An area of low pressure will bring the chance for showers and storms
to the region Tuesday night into Wednesday. There are some timing
and track differences between the GFS/ECMWF/Canadian but they all
have the low affecting the Northland. Increasing
moisture/temperature along with stronger lift from this system may
lead to strong or severe storms Tuesday night into Wednesday
evening.
Differences among the models start to amplify mid into late in the
week. The GFS develops a very strong low Thursday into Friday and is
slow moving it through with it lingering into Saturday night. The
Canadian and ECMWF are in better agreement with a weaker wave aloft
and therefore surface low. The models have all been struggling
during this time period and each has shown considerable differences
from run to run. We have periodic chances for showers/storms
Thursday/Friday for now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 635 PM CDT Fri Jun 23 2017
Diurnally driven showers and VFR cu field covers the terminals at
the start of the forecast. Expect the showers to end around
sunset. Cu field will flatten and expand into a widespread stratus
field shortly thereafter with MVFR cigs. Gusty surface winds will
also diminish by sunset. An improvement in cigs to VFR is forecast
around 16Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 50 61 49 61 / 30 30 30 60
INL 49 60 48 61 / 40 60 50 60
BRD 48 61 49 64 / 0 50 20 20
HYR 51 64 48 62 / 40 50 20 50
ASX 51 63 49 63 / 50 30 20 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...GSF
SHORT TERM...JTS
LONG TERM...Melde
AVIATION...GSF
Area Forecast Discussion
National Weather Service GRAND JUNCTION CO
457 PM MDT Fri Jun 23 2017
.SHORT TERM...(Tonight through Saturday night)
Issued at 239 PM MDT Fri Jun 23 2017
Mostly sunny skies are in place across the forecast area this
afternoon along with a milder airmass. This milder airmass is
resulting in cooler temperatures district wide. Currently at
Grand Junction Regional Airport it is 89 degrees which is 8
degrees cooler than it was 24 hours ago. On average temperatures
are running 5 to 10 degrees cooler around the area than what was
observed 24 hours ago.
As previously stated mostly sunny skies are being reported across
the area. However, GOES-16 visible satellite imagery continues to
show the Brian Head fire burning near Cedar City Utah. Smoke from
this fire is headed east. HRRR smoke dispersal modeling does show
smoke from this fire pushing into southeastern Utah and
southwestern Colorado this evening. Therefore, have added smoke
into the forecast for these geographic areas into the early
morning hours. Otherwise, mostly clear conditions and dry weather
are anticipated through at least Saturday night.
.LONG TERM...(Sunday through Friday)
Issued at 239 PM MDT Fri Jun 23 2017
The current satellite water vapor image is showing a ridge of high
pressure positioned along the California coast with a low pressure
system diving south from Saskatchewan into North Dakota. The 1200Z
ECMWF and 1800Z GFS20 have initialized well with these synoptic
scale weather features and remain in good agreement through at
least next Wednesday.
Both of these forecast models indicate that the ridge of high
pressure currently positioned along the California coast will
slide east over intermountain west this weekend resulting in
increasing temperatures into the first half of the work week.
Temperatures will decrease a few degrees on Wednesday as the ridge
flattens. Model agreement does break down mid-week, but both
models do show a broad trough of low pressure working its way
across the western states the second half of the work week
resulting in cooler temperatures and potentially some showers and
thunderstorms across northern portions of the CWA. Confidence is
low on these showers and thunderstorms therefore have not
introduced them into the forecast package yet.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 457 PM MDT Fri Jun 23 2017
Dry northwest flow will keep clouds and showers at bay across the
region through the next 24 hours. Smoke from the Brian Head fire
in southwest Utah could bring a thin haze to KDRO tonight.
Otherwise, look for VFR conditions with no CIGS at TAF sites in
eastern Utah and western Colorado tonight and tomorrow.
&&
.FIRE WEATHER...
Issued at 239 PM MDT Fri Jun 23 2017
Beginning on Saturday a warming trend will be in place across the
fire district through the middle of next week. The ridge of high
pressure responsible for this warming trend will begin to flatten
on Wednesday of next week promoting cooler temperatures and an off
chance of afternoon convection. Forecast confidence is low so have
not introduced convection into the forecast. Otherwise,
northwesterly winds are anticipated to increase on Saturday across
fire weather zone 207 (southwestern Colorado). Although, for a
brief period of time winds and RH will approach critical fire
weather thresholds a Fire Weather has not been issued for the
area. This is mainly due to the brief period of time in which
these conditions are expected to be met and the limited size of
the geographical area expected to be impacted by these
conditions.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&
$$
SHORT TERM...Larry
LONG TERM...Larry
AVIATION...NL
FIRE WEATHER...Larry
Area Forecast Discussion
National Weather Service Grand Rapids MI
1054 PM EDT Fri Jun 23 2017
LATEST UPDATE...
Marine
.SYNOPSIS...
Issued at 330 PM EDT Fri Jun 23 2017
Colder than normal temperatures can be expected this weekend
through early next week, with widely scattered showers and
thunderstorms. Rainfall will not be excessive.
&&
.UPDATE...
Issued at 850 PM EDT Fri Jun 23 2017
I added a 20 to 30 pct chance of showers to area near and west of
US-131 for this evening as the shortwave currently crossing
central Wisconsin moves over Lake Michigan. A few showers have
developed ahead of the shortwave but there is a lot of dry air at
lower levels for these showers to overcome. I am thinking they
will die off as they move inland this evening.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 330 PM EDT Fri Jun 23 2017
Trough aloft and series of vorticity maxima/shortwaves sliding
through the northwest flow will bring periods of cloudiness and
scattered showers over the weekend.
Best coverage of convection, and the best time for a few tstms,
should generally be in the afternoon and evening hours when the
diurnal contribution/instability is highest. Also,the lake shadow
should tend to focus things inland from lake Michigan.
Lowering freezing heights through the weekend may eventually lead to
a chance of some small hail in some of the low topped convection,
which would be more possible on Sunday than on Saturday.
Scattered/intermittent nature of the convection of the weekend
should lead to total QPFs of generally no more than a quarter
inch, with highest amounts north of I-96.
.LONG TERM...(Monday through Friday)
Issued at 330 PM EDT Fri Jun 23 2017
Monday will see cooler than normal weather with diurnal enhancement
of showers and a few thunderstorms as upper level troughing brings
steep lapse rates. No severe weather is expected although the
storms could bring small hail during the afternoon as freezing
levels are unusually low.
The trough axis moves east by Tuesday with shortwave ridging
returning Wednesday along with warming temperatures. We will also
see moisture return in southwest flow with chances for rain by
Wednesday afternoon. Surface low center tracks north of Lower
Michigan on Thursday and showers and thunderstorms along and ahead
of trailing cold front will persist into Friday as the front sags
south of Lower Michigan and stalls across the Ohio Valley.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 727 PM EDT Fri Jun 23 2017
Expect VFR conditions to prevail through Saturday night. That
said, there are several short waves rotating around the upper low
that will move across SW Lower Michigan both tonight and Saturday.
For tonight skies will be nearly clear for most areas but for GRR
and MKG there may be mid clouds through most of the night (shown
by the HRRR and NAM PCT CLOUD forecast). Winds will become lighter
overnight so it would not be impossible for a little fog toward
morning but I feel there will be enough mixing to mitigate that.
Also during the day time hours of Saturday the air will be
unstable but with west winds only the TAF sites near I-69 have a
significant threat for convention. I limited the VCTS to those
locations. Even then if anything does develop it will be brief.
&&
.MARINE...
Issued at 1054 PM EDT Fri Jun 23 2017
Given how cold the air coming in is relative to the Lake Michigan
surface water temperatures, it seems more than reasonable to
believe 3 to 5 foot waves are expected Saturday into Sunday near
and south of Muskegon. So I issued both a SCA and beach hazard
statement from Saturday morning till Sunday evening.
&&
.HYDROLOGY...
Issued at 257 PM EDT Fri Jun 23 2017
Major flooding is expected along the Chippewa River in Isabella
County and sharp rises are also occurring along the Muskegon basin
and will continue the next couple days as the crest moves down
the river. From 3 to 5 inches of rain fell last night combined
with earlier heavy rains.
The good news is that no heavy rain is expected through the
middle of next week which will allow those areas that are flooding
to recover. The next chance for significant rain will be Thursday
of next week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 6 AM EDT Saturday through Sunday
evening for MIZ056-064-071.
LM...Small Craft Advisory from 6 AM Saturday to 8 PM EDT Sunday for
LMZ844>848.
&&
$$
UPDATE...WDM
SYNOPSIS...Meade
SHORT TERM...Meade
LONG TERM...Ostuno
AVIATION...WDM
HYDROLOGY...Ostuno
MARINE...WDM
Area Forecast Discussion
National Weather Service Houston/Galveston TX
920 PM CDT Fri Jun 23 2017
.DISCUSSION...
A cold front was located from near Texarkana to just south of
Hobbes,NM at 7:00 PM. Storms were developing along and ahead of
the front over southern AR. Water vapor showed an upper low over
the southern Gulf of Mexico. An elongated moisture axis was
present west and northwest of this low over the central Gulf while
a dry area was further west over the Upper and Middle Texas
coastal waters.
The 00Z NAM12 was pushing the storms over AK southward toward SE
Texas overnight tonight. However, the model showed a weakening
trend in the storms with very little coverage by the time the
storms reached into the northern portions of the forecast area.
Better chances will occur after mid morning as the front moves in
from the north and the deeper layer moisture over the Gulf arrives
from the southeast. The latest models pretty much agree with the
current forecast. Did tweaked the rain chances mainly to take out
the isolated rain chances over the north and add isolated rain
chances over the offshore coastal waters for the rest of this
evening.
40
&&
.PREV DISCUSSION... /ISSUED 629 PM CDT Fri Jun 23 2017/
AVIATION.../00Z TAF/
Surface analysis has cold front boundary from Arkansas along the
Red River to west Texas. This has allowed for a line of storms to
form in Arkansas. Warm sector airmass over much of Texas south of
the boundary remains relatively capped except for west Texas.
Tonight we need to monitor the evolution of the convection
organizing in Arkansas. The 12Z WRF-ARW and TX Tech WRF-ARW both
show this line of storms pushing south and even southwest towards
KCLL to KUTS by 06-09Z Saturday. The KCLL/KUTS/KCXO TAFs may need
to be adjusted for this evolution but will wait and see for now.
Outflow may play a role in tomorrow`s convection for the area but
for now these models do not show much redevelopment of storms
until the afternoon like most other models. The TX Tech WRF does
start storms around 16-17Z along the coast so may need to adjust
the VCTS used in the TAFS for 18Z. HRRR is less robust with the
outflow and any storms redeveloping but still need to watch its
trends.
Otherwise TAFs will be close to the previous 18Z update with MVFR
ceilings overnight and mention of showers starting in the morning
hours turning to VCTS.
Overpeck
PREV DISCUSSION... /ISSUED 342 PM CDT Fri Jun 23 2017/
DISCUSSION...
A hot afternoon is well underway for Southeast Texas with 3 PM CDT
temperatures in the low to mid 90s inland and heat index values
ranging from 98 to 107. Visible satellite imagery shows a
scattered to broken stratocumulus deck developing around 4500 feet
and spreading south within an area of isentropic lift on the 310 K
surface. RAP guidance shows this area of lift gradually
translating east over the next few hours (likely as the remnants
of Cindy pull farther away from the region), allowing at least
some of these clouds to translate towards the south and east with
it. For those areas lucky to get some shade from these clouds,
temperatures may quickly drop 2-3 degrees and provide some relief
from the heat. Otherwise, cannot rule out a stray shower along the
coast or across the far extreme eastern counties through the
remainder of the day but this would be the exception and not the
rule.
Not much cooling is expected overnight with lows only falling into
the mid 70s to low 80s, but rain chances will increase across the
region on Saturday and Sunday as Southeast Texas remains situated
in a relative upper level weakness between two ridges. Speed
convergence along the coast Saturday will result in scattered
morning showers, with the northern counties seeing a thunderstorm
complex along an approaching (weak) cold front also during the
morning hours. Regional radar mosaic already shows storms
beginning to develop along this cold front across portions of the
Low Rolling Plains and along the Red River, with additional
upscale growth into a thunderstorm complex expected through the
remainder of the afternoon and evening hours as the front pushes
south towards the region.
The cold front looks to make a run for the Interstate 10 corridor
through the remainder of the morning hours Saturday, stalling
near or north of it as a sea breeze pushes inland during the late
morning and afternoon hours. Daytime heating and the collision of
both of these boundaries is expected to result in the development
of scattered to numerous showers and thunderstorms on Saturday,
with greatest coverage centering wherever the boundaries collide
(likely near Interstate 10). Convection should wane with loss of
heating by Saturday evening. Another round of morning showers are
expected on Sunday, with scattered to numerous thunderstorms again
developing with daytime heating and likely focusing along
wherever the remnant frontal boundary (or outflow boundaries from
Saturday`s convection) is. The front won`t have much of an effect
on temperatures but increased clouds on Saturday and Sunday will
keep temperatures a few degrees cooler than today with highs in
the mid 80s to low 90s.
Similar to what the previous forecast noted, storm motions will
be very slow both days (around 5 knots Saturday, 10 knots Sunday)
and this, combined with precipitable water values 1.8-2 inches,
will result in the threat for locally heavy rainfall and the
potential for some localized flood issues as thunderstorms have
the potential to remain nearly stationary before collapsing. SREF
plumes show forecast rain totals generally in the 1-2 inch range
during this time, but would not be surprised to see some isolated
2-3 inch totals occur given the aforementioned environmental
conditions. Will also have to keep an eye on a gusty wind threat
as well on Saturday. Relative humidity progs show drier air
evident over the northwest Gulf on afternoon water vapor imagery
working its way into the region from the south/southwest. This
drier air would help enhance evaporational cooling, accelerating
downdrafts and creating the potential for gusty winds in stronger
convection on Saturday.
The region remains under this relative weakness in the upper flow
through the middle of the upcoming week, with mainly daytime
shower and thunderstorm chances inland through mid-week.
Expect these chances to gradually decrease early to mid next week
as 500 MB heights increase and atmospheric moisture content drops
a bit. These increasing mid-level heights and decreasing rain
chances will also result in gradually warming temperatures with
highs increasing to near or slightly above normal (low to mid 90s)
by the end of the next work week.
Huffman
MARINE...
Winds are slowly diminishing today, and seas should also come
down with them on a bit of a delay. Though winds may not quite be
at the SCEC threshold, the lag in waves should justify keeping it
in place into tonight. Going into the weekend and early next week,
light to moderate flow is expected, generally onshore. An
approaching front may back winds slightly to more easterly from
Sunday, but will still be generally onshore. Some stronger winds
may be possible mid to late week.
Tides also remain elevated, and astronomical high tide at around
two feet at Galveston are not aiding matters. Another chance at
coastal flooding in vulnerable areas around high tide early
tomorrow morning can`t be ruled out. Will hold off on another
Coastal Flood Advisory for now to gauge tidal behavior through low
tide and into the upswing towards high tide.
Luchs
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 77 90 73 87 71 / 20 40 50 60 30
Houston (IAH) 78 90 75 87 73 / 20 70 40 70 40
Galveston (GLS) 81 88 80 87 78 / 30 40 20 50 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 10 PM CDT this evening
for the following zones: Coastal waters from Freeport to
the Matagorda Ship Channel out 20 NM...Coastal waters from
High Island to Freeport out 20 NM...Waters from Freeport to
the Matagorda Ship Channel from 20 to 60 NM...Waters from
High Island to Freeport from 20 to 60 NM.
&&
$$
Discussion...40
Aviation/Marine...39
Area Forecast Discussion
National Weather Service Indianapolis IN
1022 PM EDT Fri Jun 23 2017
.UPDATE...
The AVIATION Section has been updated below.
&&
.SYNOPSIS...
Issued at 200 PM EDT Fri Jun 23 2017
A Cold front over Central Indiana will push east and exit the
state tonight. Rain will end late this afternoon and evening as
the front passes. High pressure centered over the western plains
states will then build across the Indiana and the Great
Lakes...providing cooler and drier NW flow. This will result in
dry and pleasant weather this weekend...with below normal
temperatures and comfortable humidities.
Dry weather and below normal temperatures will be expected for
much of next week due to the strong high pressure system to the
west.
&&
.NEAR TERM /Tonight/...
Issued at 645 PM EDT Fri Jun 23 2017
Planning on canceling the Flash Flood Watch early as the heavy
rain threat has pushed out of the forecast area. Lingering shower
activity over the southeast zones will probably end around
240100Z.
Previous discussion follows.
Surface analysis shows a Cold front across NW Indiana stretching
to East Central Illinois to SE Missouri. Radar trends show a band
of showers ahead of the front across central Indiana. Some of the
showers continue to produce very heavy rain with the very moist
tropical air mass in place.
GFS and NAM continue to suggest a SE progression of the surface
cold front which will effectively push the stream of moisture SE
and out of Central Indiana. Rapid refresh suggests that by
00Z...only the far southeastern parts of the forecast area will
still be impacted by rain. HRRR progression after that suggests
the forecast area should be rain free by 03Z. Time heights show a
complete loss of forcing and strong drying within the column after
00Z with subsidence. Significant air mass change is also expected
as dew points in the lower 60s and upper 50s...as seen in NRN
Illinois...are set to arrive in the wake of the front.
Thus will trend toward a dry forecast tonight...especially across
the NW where Rain will have ended. May need to keep some pops for
the first 1-2 hours after 00Z across the SE where rain may not
have exited yet. Models suggest strong cold air advection tonight
and will trend lows at or below the expected forecast builder
blend.
&&
.SHORT TERM /Saturday through Monday/...
Issued at 200 PM EDT Fri Jun 23 2017
GFS and NAM suggest a large broad trough in place across the
Great lakes and Ohio valley through Monday. Several weak...poorly
organized disturbances look to pass within the flow...but best
dynamics look to remain well north of Central Indiana. Time
height sections continue to show a dry column through Monday.
Forecast soundings through Monday also show a dry column...but
attainable convective temperatures in the upper 60s to near 70.
However on both Saturday and Sunday afternoons...forecast
soundings show a good mid level inversion that should just result
in some flat topped CU. Furthermore CAPE appears really limited
with values less than 300 J/KG. Thus with dew points in the 50s
and high in the 70s expected for this
period...comfortable...pleasant and not humid weather is expected.
Thus will trend toward Partly cloudy days and Mostly clear nights.
Forecast soundings hint at slightly more CAPE on Monday afternoon
and less of a mid level cap. Forecast blender may try to insert
pops here...however...confidence remains very low at this point
given the NW flow expected and a lack of deep moisture.
&&
.LONG TERM /Monday Night through Friday/...
Issued at 220 AM EDT Thu Jun 22 2017
Next week will generally begin a bit cooler than normal and with a
spotty shower possible as an upper low exits the Great Lakes.
Temperatures will warm gradually, returning to near normal during
the week as upper level flow becomes more zonal and then weakly
anticyclonic by week`s end. A frontal zone will move toward the
region during the latter portion of the week, returning thunderstorm
chances to the area.
Blended initialization handled things well and only minor tweaks
were necessary.
&&
.AVIATION /Discussion for the 240300Z KIND TAF Update/...
Issued at 1022 PM EDT Fri Jun 23 2017
No significant changes made to the forecast at this time. Previous
discussion follows.
Lingering shower activity expected to pass off to the southeast of
the terminals by issuance time based on radar loop. Satellite
shows rapid clearing of the lower cloud cover over northwestern
Indiana, so expected most of the cloud cover below 050 to scatter
out during the early evening hours.
Some concern about fog development later tonight given today`s
rainfall, but with drier air advecting in, confidence is low at
this time.
Surface winds 330-350 degrees at 9-12 kts early this evening will
diminish to 5-8 kts after dark and gradually back to 290-310
degrees by sunrise Saturday.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Puma
NEAR TERM...Puma/JAS
SHORT TERM...Puma
LONG TERM...NIELD
AVIATION...JAS
Area Forecast Discussion
National Weather Service Lake Charles LA
1024 PM CDT Fri Jun 23 2017
.DISCUSSION...
Extensive outflow boundary and associated convection continues to
push south across north LA, with additional isolated activity
occurring farther south over East/South Central LA. HRRR runs have
continued to show the activity to the north progressing south into
the forecast area after midnight, though the intensity is shown
to wane over most of the area. The notable exception is where it
intercepts the presumably still active convection over S Central
LA. Have adjusted PoP/Wx grids based on latest radar trends and
the HRRR. No other changes to the forecast required this evening.
13
&&
.PREV DISCUSSION... /issued 700 PM CDT Fri Jun 23 2017/
AVIATION...With the exception of a few showers over lower
Acadiana, convection has temporarily ended over the area. Did
introduce some activity returning after midnight. This associated
with a southward propagating MCS now over central Arkansas, with
the latest HRRR suggesting could maintain itself into our area.
Otherwise, VFR is expected to prevail. Shower and thunderstorm
chances will be increasing during max heating Saturday as
tropical moisture remains plentiful.
PREV DISCUSSION... /issued 344 PM CDT Fri Jun 23 2017/
DISCUSSION...
Showers and thunderstorms this afternoon have continued to
gradually shift to the east this afternoon with the low level
convergence axis shifting off to the east. Also water levels
continue to remain elevated along, especially in the coastal lakes
and bays this afternoon. The PETS Guidance continues to show
elevated water levels gradually subsiding. With a pretty large low
tide beginning shortly will allow the advisory to expire at 6 PM.
The guidance still indicates potential for 1-1.5 feet of
inundation tomorrow morning with high tide, but will let the
evening shift or the mid shift get another run of the guidance
before extending it. After tomorrow morning that should be the
last advisory potential coastal flooding for this event.
Front still forecast to sag into the region Saturday and gradually
wash out near the coast. This will cause the the chance for
showers and thunderstorms to increase for the weekend. Despite
rainfall forecasts being reduced slightly this forecast cycle. The
high PWAT airmass in the wake of Cindy will aid in high rainfall
rates, so some locations could get some hefty amounts and thus a
small risk of exceeding flash flood thresholds.
Rain chances will remain elevated through Monday before getting
back to more climatological values.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 75 86 71 85 / 50 60 30 50
LCH 78 88 74 86 / 30 60 40 70
LFT 76 86 74 85 / 50 70 40 70
BPT 77 88 74 85 / 20 50 30 60
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service New Orleans LA
408 PM CDT Fri Jun 23 2017
.SHORT TERM...
Southwesterly flow in place across the area in response to the
broad circulation of remnant Cindy currently moving into the Ohio
Valley. The frontal zone is being drawn southward with an
extensive coverage of convection reaching central Louisiana. This
convection will likely continue into the evening and quite
possibly overnight. The HRRR runs this afternoon is advocating an
outflow QLCS advancing southward after midnight, but other models
are focused mainly along the frontal zone itself. Will maintain
40-50 percent in the overnight, then carry into Saturday. The rain
trends will have to be closely monitored for echo training as
efficient tropical airmass becomes involved with the frontal zone
that will probably be moving on the impetus of the convection.
Frontal zone stalls out for continued chances of rain Sunday.
Temperatures will vary widely depending on rain coverage but
generally in the upper 80s for highs though one or two locations
may attain 90 either day.
.LONG TERM...
Models show enough troughing aloft to possibly push the front into
the north gulf for a very brief dry period Monday before moist
begins to surge northward Tuesday. Bermuda ridge regime becomes
established to bring the area under a more typical summer sea
breeze pattern for the latter part of the forecast period. 24/RR
&&
.AVIATION...
A very moist and unstable pattern will continue to bring widespread
showers and storms into the area. Convection will continue to
increase from nw to se...peaking between 2100 and 00z this evening
bringing conditions down from MVFR to IFR during the heavier storms.
Convection expected to gradually diminish after 02Z. Lower ceilings
expected to drop down below 2000 feet between 06 and 12z. Convection
will begin to refire after 15z on Saturday and continue to become
more widespread throughout the late morning into the afternoon
hours.
&&
.MARINE...
Winds and seas are finally relaxing from the affects of Cindy with
more favorable conditions this weekend as pressure gradient
relaxes. Frontal zone not expected to push much into the gulf
before stalling and drawn northward early next week, thereby
onsetting a steady state onshore flow pattern for the rest of the
week.
&&
.DECISION SUPPORT...
DSS code: Blue.
Deployed: None.
Activation: None.
Activities: Monitoring Hydro/Convective trends
Decision Support Services (DSS) Code Legend
Green = No weather impacts that require action.
Blue = Long-fused watch, warning, or advisory in effect or high
visibility event.
Yellow = Heightened impacts with short-fused watch, warning or
advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
tropical events; HazMat or other large episodes.
Red = Full engagement for Moderate risk of severe and/or
direct tropical threats; Events of National Significance.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 73 84 71 83 / 50 80 50 60
BTR 75 87 73 84 / 40 80 50 60
ASD 75 88 74 84 / 40 50 40 60
MSY 76 88 75 84 / 40 50 30 60
GPT 76 86 75 83 / 40 40 40 60
PQL 74 87 73 84 / 20 50 50 50
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Coastal Flood Advisory until 4 PM CDT this afternoon for LAZ040-
050-058-060>062-064-066>070-072.
GM...Small Craft Advisory until 4 PM CDT this afternoon for GMZ532-
534-536-538-550-552-555-557-570-572-575-577.
MS...Coastal Flood Advisory until 4 PM CDT this afternoon for
MSZ080>082.
GM...Small Craft Advisory until 4 PM CDT this afternoon for GMZ534-
536-538-550-552-555-557-570-572-575-577.
&&
$$
24/RR
Area Forecast Discussion
National Weather Service Lubbock TX
616 PM CDT Fri Jun 23 2017
.AVIATION...
Winds behind front continue to remain gusty, though thunderstorm
chances look to be dwindling quickly for all sites. MVFR cigs
expected to develop overnight. KLBB could possibly dip to IFR
briefly at times.
&&
.PREV DISCUSSION... /issued 306 PM CDT Fri Jun 23 2017/
DISCUSSION...
Convective chances are somewhat unclear from this afternoon
through the next several days.
Convection has developed along an advancing cold frontal boundary
oriented east-west from the southern South Plains through the southern
Rolling Plains. Temperatures in excess of 100 degrees with surface
dew points around 50 will support high bases and therefore a wind
threat. This front will bring markedly stronger northeasterly
winds and these winds will continue overnight. This cold front
will bring a very welcome break to the oppressive heat we have
experienced that past week or so. Surface ridging will build in
overnight behind this front with decreasing winds by mid morning.
A subtle short wave aloft may bring thunderstorms from
southwestern Oklahoma to the Rolling Plains tonight. However, this
convective activity is far from certain. It is now supported by
the HRRR and is supported by the TTU WRF to an extent. Elevated
instability above the frontal boundary will not be in short supply
within strong moist southeasterly winds giving some confidence in
this possible overnight convection.
Extensive low level stratus casts doubt on convective chances for
Saturday especially during the daytime hours. Moist isentropic
upglide will keep elevated instability around the area which may
be enough to generate scattered showers and thunderstorms. Models
are again mixed on how Saturday will play out but widespread severe
convection is not anticipated. Northwest flow storms will be more
difficult to come by on Saturday evening but will have stronger
chances on Sunday evening. Low level flow will be more out of the
southeast rather than east with increased instability across the
area into eastern New Mexico. Another day with possible northwest
flow storms will occur on Monday with a continued weak upper level
ridge to the west.
This upper ridge will be suppressed for several days this weekend
into early next week as an upper level system moves into British
Columbia. Tuesday and beyond bring more uncertainty to the
forecast as the upper level ridge begins to strengthen again
leading to increasing heights. Models are differing on the
strength of the system moving out of British Columbia which will
affect the strength of the upper ridge. However, this may only
mean a difference locally of either 90 or 100 degrees by late next
week.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
99/99/74
Area Forecast Discussion
National Weather Service Nashville TN
940 PM CDT Fri Jun 23 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Cold front now entering northwest sections of the mid state. Light
northwest flow evident to the north of the boundary with dewpoints
slowly dropping into the 60s. light isol/scattered shower activity
still ongoing southeast of the boundary. Latest HRRR data shows
decreasing shower activity from west to east and we continue
through the overnight. Will maintain a chance of showers over
most of the area until 06z. At that time...pops will decrease
markedly across much of the northwestern half of the midstate.
Otw, temps appear to be on track. Will see lows of 65 to 70
degrees by daybreak.
Update out shortly.
&&
.AVIATION...
18Z TAF DISCUSSION.
CKV/BNA/MQY/CSV....Main concern for terminals will be impacts of
shwrs/sct tstms along with sfc gust to 30kts at times as broad
area of shwrs/sct tstms associated with the remnants of Tropical
Depression Cindy continues to move across the mid state region
thru 24/00Z. Although technically not defined as LLWS, gusts 40 to
50kts within 1 kft of sfc probable. Sfc frontal passage 24/06Z W
to 24/12Z E should usher any remaining shwrs east of mid state
region, with VFR/SKC conditions across entire mid state by 24/12Z.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......21
AVIATION........Shamburger
Area Forecast Discussion
National Weather Service Pittsburgh PA
1007 PM EDT Fri Jun 23 2017
.SYNOPSIS...
A cold front sweeping through early Saturday will return
comfortable humidity levels by the weekend. Below normal
temperatures greet us early next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
Tweaked forecast to reflect current radar trends. The heaviest
rain rates appear to be over with. We will be conducing a damage
survey for Greene and Fayette counties Saturday and likely into
West Virginia.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
Dry and less humid air will be welcome news for many this
weekend as dewpoints drop into the 50s. Northwest winds behind
the baroclinic zone will clear out the sky during the morning,
however moisture will be on the increase as a fast moving
shortwave trough crosses during the evening hours. The column is
fairly dry, so no measurable QPF is foreseen Saturday. Dry
weather continues for the second half of the weekend despite
less sunshine. Yet another passing short wave will bring clouds
and given its stronger than the one Saturday isolated showers
are possible north of the I-76 corridor in the late afternoon /
early evening hours Sunday.
Mid level heights continue to fall as we kick off a new work
week. Most of the energy will reside along the lakes, so precip
chances are small over northern WV and western MD when compared
to northwest PA. Any shower will be brief. The bigger story is
the spring like feel as daytime high temps do not leave the 60s
Monday! This will be almost 15 degrees below normal.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
Highlights:
- Cool start - warm end temp wise
- Unsettled weather returns Friday
- No heat waves or high water threat
Mid level heights increase with a ridge building into the
eastern United States. This will bring temps back to normal
levels by Thursday and above normal by a week from now.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR weather will yield to MVFR and IFR cigs this evening in wake
of the cold front. Drier air will work into the area toward 12Z
bringing terminals back to VFR where they will stay for the
balance of the forecast. Winds will be gusty from the WSW
tomorrow afternoon with peak gusts around 20 kts.
.OUTLOOK...
Upper trough may bring occasional restrictions Sun and Mon in
afternoon showers/storms.
&&
.HYDROLOGY...
The flash flood watch remains on track. The axis of highest QPF
has shifted a little north to far southern PA where 24 hour
amounts in excess of three inches are possible. HRRR shows a
several hour period of moderate to heavy rainfall thankfully it
is across a region that was not impacted by the nearly 4-6" of
rain that fell in parts of Indiana county last evening.
Warm rain process and PRE setup remain in place. PWATS are
pushing two inches while warm cloud depths are in excess of
13kft. The low level jet continues to pump moisture from Cindy
into our region. All of these point to enhanced convergence
ahead of the front.
River forecasts have been tweaked upward across Mon and
headwaters of Ohio river. We still do not have any forecast
points going to flood, but Pittsburgh, Elizabeth, and Charleroi
are predicted to reach action stage.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...Flash Flood Watch until 2 AM EDT Saturday for MDZ001.
OH...Flash Flood Watch until 2 AM EDT Saturday for OHZ039>041-
048>050-057>059-068-069.
PA...Flash Flood Watch until 2 AM EDT Saturday for PAZ013-014-
020>023-029-031-073>076.
WV...Flash Flood Watch until 2 AM EDT Saturday for WVZ001>004-012-
021-509>514.
&&
$$
Area Forecast Discussion
National Weather Service Blacksburg VA
916 PM EDT Fri Jun 23 2017
.SYNOPSIS...
A cold front, energized by the remnants of what was Tropical
Storm Cindy, will progress east across the forecast area
tonight. Showers and embedded thunderstorms are anticipated into
the overnight, a few of which may produce gusty winds and heavy
downpours. The cold front will slowly push southeastward into
eastern Virginia and North Carolina on Saturday, followed by a
cooler and much drier air mass for the rest of the weekend.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 855 PM EDT Friday...
Leading edge of weakening convection to the west slowly heading
east toward the western counties attm in association with the
Cindy remnant racing through NE Kentucky and into West Va. Once
the low passes should see shra/tsra get a bit better push off to
the southeast with perhaps low topped bands impacting the
mountains into the early morning hours. However latest regional
radar loops show a weaker area of showers within the line
heading toward southwest VA likely due to strong lift just north
and a passing storm cluster to the west. This may tend to fill
in and intensify given the passage of the main core of 850 mb
winds across the western sections in the next few hours and low
level instability off evening soundings but iffy.
Other concern is with the heavy rain potential mainly northwest
sections as the persistent band of heavy rain now northwest of
RLX drops southeast once the remnant low passes. Some solutions
including the HRRR do bring between 1 and 2 inches to portions
of Greenbrier county between 03-09Z while others weaken the
heavier rainfall once better support exits. Given uncertainty
and isolated nature to possible heavy rain, wont hoist a watch
and handle with short term products if needed at this point.
May also see some of the showers push east of the mountains
after midnight but in a much weaker state. Thus main update was
with timing of higher pops northwest and to bump up QPF mainly
Greenbrier/Summers into Bath county. Otherwise expecting a
breezy and very muggy overnight with higher gusts possible in
showers despite lack of thunder. Lows 60s west to low/mid 70s
east.
Appears exodus of showers will occur a bit faster later tonight
with decent drying developing by early Sat. Since this supported
by most solutions, opted to lower pops by daybreak Sat and
remove most chances during the morning for now.
Previous discussion as of 339 PM EDT Friday...
While currently on the quiet side, heading into a more active
evening with several potential issues to contend with, owing to the
approaching cold front which has merged with Cindy`s remnants.
Through the rest of the afternoon.... we continue to carefully
monitor the potential for isolated thunderstorms. Visible
satellite reveals some cloud breaks taking place from the
central/southern Blue Ridge eastward. LAPS-based CAPE values are
on the order of 1000-1500 J/kg, and we do have strong low-level
winds already in place (40-50 kts are common per area VWPs).
The strong low-level winds contributing to deep layer shear
values near 40 kts per SPC mesoanalysis. If any isolated storms
do develop, as reflected in recent runs of the HRRR and the 3-km
NAM, they may produce localized gusty winds as they move
northeastward off the Blue Ridge. Otherwise, looking at
generally quiet conditions into the early evening.
For tonight... weather turns increasingly more active, as we
will watch ongoing storms across the Ohio and Tennessee Valleys
progress eastward across the forecast area. Present indication
from a consensus of high-resolution guidance is to bring an
evolving line of heavy showers and embedded thunderstorms into
our western WV/VA/NC doorstep by around 01z, progressing
eastward to the Blue Ridge foothills toward midnight. While it
is a diurnally unfavorable period of time for strong convection,
wind shear values both through the lowest 0-3km and deep layer
owing to Cindy`s wind field only increase. Though it`s difficult
to fully trust higher-resolution guidance later in the model
cycle, through midnight several members do depict some
concerning radar structures as storms move into far western
counties. I suspect that we`ll have a high-shear/low-CAPE
environment in place tonight, even well after dark. In that
environment, even heavy showers could offer the potential to
produce gusty winds which may topple dead or shallow-rooted
trees. Based on 0-1 km shear values progged to be in the 40 to
50 kt neighborhood, this also poses a concern for isolated
embedded spin-ups in stronger convective elements in the line.
Given those reasons, to raise awareness of the potential threat
I`ve added enhanced wording for gusty winds in the zone forecast
through midnight at least, roughly from the Blue Ridge
foothills westward into southeast WV. After midnight, heavier
showers and storms seem to lose structure as they drift into the
Piedmont areas, so I`ve kept the gusty wind wording to central
and western counties away from the VA/NC Piedmont areas.
Another concern in this humid, tropical air mass will be heavy
rainfall potential. Even showers should be efficient rainfall
producers. Potential for hourly rain rates to be enhanced by
convective elements as well. I`ve maintained heavy rainfall wording
in the zones for the tonight period. Fortunately, rainfall we did
receive last night was not substantial. And the fast-moving nature
to tonight`s rain/thunderstorms will probably keep flooding more
localized. Guidance QPF values continue to generally paint some
consensus in depicting the highest forecast values northwest of our
forecast area, and official forecast ranged from a half to one inch
west of I-81, a quarter to third of an inch to the Blue Ridge
escarpment, tapering to a couple tenths or less east. For those
reasons, confidence was too low on an issuance of a flash flood
watch with this forecast package. For more on hydro, see the
Hydrology section below.
Cold front will have advanced east of the Blue Ridge toward Saturday
morning. However, the 12z NAM, ECMWF and GFS suggest that the front
may make more slow southeastward progress into the NC Piedmont and
foothills areas. While much drier, more refreshing air filters into
the northwestern two-thirds of the forecast area on Saturday, I`ve
kept lower Chance level PoPs through the day for showers and
thunderstorms for the southeastern third.
With the front roughly bisecting the forecast area, lows tonight
range from the lower to middle 60s west of the Blue Ridge but will
be a muggy lower to mid 70s from the Roanoke Valley eastward. Highs
tomorrow should top out in the mid 70s to lower to middle 80s.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 339 PM EDT Friday...
By 00z Sunday (8 pm Saturday Night), most of the medium range models
forecast the position of the cold front across the far southeast
portion of our forecast area. This boundary interacting with
lingering instability will result in keeping a slight chance for
storms from South Boston to Yanceyville early Saturday evening.
Dry conditions are expected for the remainder of the short term
period as a deep northwest-west flow prevails across our region
through Monday.
In the upper levels, a broad upper trof will gradually deepen across
the Great Lakes into the northern U.S., which will allow dew points
to drop through the period resulting in cooler temperatures Monday
morning compared to Sunday morning. Leaned toward the cooler
guidance values or lows Monday morning. Highs will also be cooler
Monday as 1000-850mb thicknesses continue to fall. For late June,
humidity levels will be quite comfortable.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 339 PM EDT Friday...
The long range models are in good agreement with the overall upper
air pattern during this period with an anomalously deep upper trof
over the eastern U.S. early in this period, with 500mb heights 2-3
standard deviations below normal,transitioning to a zonal flow by
mid week, with ridging building by the end of the week.
The 12Z GFS is still fastest with the eastward progression of the
upper trof Tuesday night into Wednesday, but this has little impact
on the tranquil weather expected during this time. A weak frontal
boundary moving through early Tuesday morning may generate some
spotty showers in the mountains, but forecast RAOBS indicate there
will be very little moisture available. Otherwise, PWAT values will
remain below average until Thursday night/Friday so expect a
prolonged period of dry weather. By late in the week...a deep
southwest flow developing on the west side of an upper ridge and
ahead of an approaching upper trof in the upper mid west will
increase moisture and provide the opportunity for weak upper level
disturbances to pass over our area. This will result in increase
chances for scattered thunderstorms during this period.
As for temperatures, forecast 850mb temps from the GEFS are 2-3
standard deviations below average, which will lead to some cool
mornings Tuesday and Wednesday. Adjusted low temperatures down a
couple of degrees below guidance during this period. Temperatures
will moderate late in the week.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
As of 650 PM EDT Friday...
Overall active aviation forecast period in the first 12 hrs.
VFR conditions should prevail into early this evening across the
mountains and out east through about midnight. Areas of
mechanical turbulence along the spine of the Blue Ridge are
likely to continue into this evening as the low level jet ramps
up to around 50 kts ahead of convection to the west. Surface
winds should also remain gusty at times with KBLF perhaps
gusting to 30 kts at times.
Deterioration to sub-VFR flight conditions will occur from west
to east after sunset with most of the showers either passing
east or dissipating during the early morning hours of Saturday.
This ahead of a cold front along with the remnants of Cindy that
are likely to produce at least a broken band of moderate to
heavy showers and embedded thunderstorms. Models have continued
to slow down the eastward progress of this line while showing a
weaker scenario with best energy passing by to the northwest.
Thus have only included a prevailing period for showers at
KBLF/KLWB with continued VCSH/VCTS and TEMPO elsewhere although
thunder chances look rather small at this point. Appears some
low clouds may develop across the mountains as the showers exit
with potential IFR/LIFR mainly around KBLF late. Strong wind
gusts to 35 kts may also accompany any of the heavier showers.
For Saturday, the front should make slow but steady progress
southward, with steadily improvement to VFR conditions along
with a westerly wind at 8-15 kts with potential gusts to around
25 kts during Saturday afternoon.
Extended Aviation Discussion...
VFR conditions to then prevail Saturday night through Sunday night.
Potential for radiation fog and related visibility restrictions
Sunday night.
A cold front passing on Monday may produce VFR/possible MVFR
conditions and breezy northwest winds behind it. VFR then lasts
through Wednesday.
&&
.HYDROLOGY...
As of 911 PM EDT Friday...
Rainfall forecast/models/ensemble river forecasts suggests greater
threat for flooding will remain northwest of our forecast area
into tonight. Average rainfall amounts of .50 to 2 inches
expected from the NC mountains to Mountain empire of SW VA to
southeast WV with 2 to 4 inches further west into the KY/TN/OH
corridor.
Not seeing enough signals to warrant a watch, but given efficient
rainfall rates, any convective elements or training will increase
the threat especially across the Greenbrier Valley of West
Virginia into the overnight where the heaviest rainfall is
expected. Timing of heavy rain will be in a 3 to 6 hour window
from late this evening into early Saturday morning with drier
air quickly returning Saturday.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...AL/JH
NEAR TERM...AL/JH
SHORT TERM...PH
LONG TERM...PH
AVIATION...AL/AMS/JH
HYDROLOGY...AL/AMS
Watches/Warnings/Advisories section of this Area Forecast Discussion
for detail. Otherwise, very hot daytime temperatures to continue
this weekend, then daytime temperatures will lower closer to
seasonal normals Wednesday into next Friday.
&&
.AVIATION...Valid thru 25/00Z.
Isolated -TSRA near mountains northeast of KDUG ending early this
evening, then isolated -TSRA east of KTUS Saturday afternoon. Brief
wind gusts to 40 kts may occur. Otherwise, VFR conditions into
Saturday afternoon. Surface wind wly/nwly 10-20 kts with gusts to 25
kts diminishing this evening and becoming less than 10 kts by
24/06Z. Surface wind Saturday afternoon swly to nwly 5-15 kts with
gusts to 20 kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Isolated to scattered thunderstorms east of Tucson
Saturday afternoon and evening, then scattered thunderstorms
generally from Tucson eastward and southward Sunday into Tuesday.
Expect decreasing coverage of thunderstorms Wednesday, with isolated
to scattered thunderstorms mainly east to south of Tucson. Dry
conditions are forecast to prevail across much of the area next
Thursday and Friday.
Otherwise, gusty east to southeast winds will likely occur Saturday
night into Sunday morning. The favored locales will be the Upper
Gila River Valley including Safford, and near the Tucson metro area.
20-foot winds will then exhibit diurnal trends with speeds mainly
less than 15 mph, although some stronger afternoon gusts to occur
due to daytime heating.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM MST this evening for AZZ510-512.
Excessive Heat Warning until 7 PM MST Saturday for AZZ508.
Heat Advisory until 7 PM MST Saturday for AZZ511-513.
Excessive Heat Warning until 7 PM MST Sunday for AZZ501>507-509-515.
Heat Advisory until 7 PM MST Sunday for AZZ514.
&&
$$
Francis
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