Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/18/16
Area Forecast Discussion
National Weather Service La Crosse WI
714 PM CDT Mon Oct 17 2016
...Severe Weather Potential Quickly Diminishing...
.UPDATE...This evening
Issued at 714 PM CDT Mon Oct 17 2016
The threat for severe storms across north central Wisconsin is
really starting to diminish this evening. The main threats are
quickly turning to brief heavy rain, lightning and perhaps some
wind gusts to 30 mph. 0-1 km shear is rather strong into Clark and
Taylor Counties but now that we are really starting to lose
surface bases CAPE and CIN is building thinking the tornado
potential has passed.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 215 PM CDT Mon Oct 17 2016
The main concern in this period is with the rain chances tonight.
Water vapor satellite this afternoon shows a short wave trough
coming across Wyoming into Nebraska. This wave will continue to
move east/northeast tonight and should reach northeast Wisconsin
into the eastern part of the U.P. of Michigan by early Tuesday
morning. The wave does come through with a bit of a positive tilt
which will keep the best pv advection on the poleward side with
just some weak pv advection in the 500-300 mb layer coming across
the northern sections of the forecast area. A strong upper level
jet will come through with the short wave trough, but both the
17.12Z NAM and several runs of the RAP today indicate that most of
the area will be under the right exit region of this jet and the
subsidence associated with it.
At the surface, a low was over the Missouri River Valley near
KSUX. A cold front extended northeast from the low into northern
Wisconsin. This surface low will continue to deepen through the
day and move rapidly northeast along the cold front reaching Lake
Superior by 06Z. Visible satellite is showing an extensive low
cloud shield out ahead of the surface low in the warm sector and
even if this does start to break up at this point, there will not
be enough hours of heating to significantly add to the CAPE.
Despite this, with the unusually warm and moist airmass already in
place, ML CAPES values are in the 1000-1500 J/kg range ahead of
the cold front. Looking at the latest RAP soundings for KEAU and
KRCX, the cap in place gets weakened but may not get totally
eliminated. If this is the case, then the threat for getting
surface based storms appears to be slim, pretty much ruling out a
tornado threat. The MU CAPE does extend farther back to the
northwest into the cool sector which could still be enough to
support a large hail and damaging wind threat. The timing of any
severe threat still looks to be from late this afternoon into
early this evening before the surface low moves into the area and
pushes the CAPE out of the area. The latest sets of hi- res meso
scale models all seem to have a good handle on how things should
develop through the afternoon into the evening with the best
chances for storms generally remaining just to the northwest of
the forecast area into Clark and Taylor Counties. Plan to show a
60 to 80 percent rain chance for Clark and Taylor and then quickly
drop this down to less than a 15 percent south of Interstate 90.
This should then lift out to the northeast through the night with
the entire area expected to be rain free by late tonight.
The rest of the period looks to be dry, although another positive
tilt short wave trough looks to come across the region Wednesday
night. This wave should go south of the local area which with the
positive tilt, could bring some lift to the southern sections of
the forecast area. The front that goes through the region tonight
will be over the Ohio River Valley and there is concern whether
there will be enough moisture behind this front for the short wave
trough to work with. The 17.12Z NAM and GFS keep the area dry
while the ECMWF and GEM do show some light rain. For now, will
maintain forecast continuity and stay with a dry forecast.
.LONG TERM...(Thursday night through Monday)
Issued at 215 PM CDT Mon Oct 17 2016
Not many changes in this period as the GFS and ECMWF are still in
agreement with a longwave trough moving through the area and bringing
seasonable temperatures. Much of the period also looks dry, though
the ECMWF has consistently hinted that a shortwave may move through
Friday night into Saturday morning and bring a bit of precipitation.
While the GFS does show a similar feature, it has it farther north
and not nearly as amplified, therefore keeping all of the
precipitation north. Beyond Saturday, northwest flow will dominate
and temperatures will remain near normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 656 PM CDT Mon Oct 17 2016
IFR conditions are possible late tonight in low stratus and BR.
Otherwise, a cold front will slide through the region tonight into
Tuesday. The stratus will scatter out by mid morning Tuesday and
cloud bases will rise to VFR by late morning into the afternoon.
Look for skies to become mostly clear during the afternoon hours.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
UPDATE...WETENKAMP
SHORT TERM...04
LONG TERM...CA
AVIATION...WETENKAMP
Area Forecast Discussion
National Weather Service Taunton MA
945 PM EDT Mon Oct 17 2016
.SYNOPSIS...
A stalled front over Southern New England this evening moves north
as a warm front Tuesday morning. This will bring unseasonably
warm conditions with the potential for near record high
temperatures Tuesday and Wednesday. Unsettled weather likely at
times Thu and Fri. Not as warm late week but still mild for mid
Oct. A drying and cooling trend likely next weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
945 PM update...
Isolated showers which moved through N MA late afternoon and
evening have shifted to Essex county and will be moving offshore.
Meanwhile watching a weakening MCS moving east from northern NY.
Weakening will continue as the complex outruns low level jet
energy and what is left of the instability, but sct showers may
clip northern MA overnight per the HRRR and RAP. Will increase
PoPs north of the Mass Pike. A mild night by October standards
with mins mostly 55-60 and even a tad humid.
The other forecast consideration which may have a big impact on
temps tomorrow is a backdoor front which is pushing south across
southern ME and may get into NE MA by daybreak. Some of the hi-res
guidance holds temps in the 60s across NE MA into the afternoon
before pushing the front to the north, while other guidance keeps
the front just north of SNE. Will have to examine this in more
detail with 00Z guidance suite.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Unseasonably warm weather is in store for the region. Southwest
flow and increasing sunshine Tuesday will mix the column to at
least 900 mb. Temps at 900 mb fully mixed would support max sfc
temps around 80. If the mixing reaches 850 mb it would support mid
80s.
Meanwhile winds in the mixed layer will be around 25 knots. Expect
gusty southwest winds near 25 knots.
Dew points will remain 55 to 60 Tuesday night. This will mean
another mild night with readings in the upper 50s and low 60s. If
winds diminish sufficiently overnight, this would allow patches of
fog to form.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Highlights...
* Unseasonably warm Wednesday, with near record high temperatures
* Widespread showers possible Friday
* Drying and cooling trend likely next weekend
Wednesday...
Southeast to west winds continue, providing a little downslope
component across eastern MA. Plenty of sunshine will mean another
summer-like day. High temperatures expected to approach the
records, which are in the 81-84 degree range. See the climate
section below for more information.
A weak cold front should cross our region Wednesday night. This
front could produce some showers.
Thursday...
A weak front along the the south coast of New England is
anticipated to move back north as a warm front during the day.
While this front is nearby, cannot rule out the possibility for
some showers during the day. More clouds and easterly winds should
mean seasonable high temperatures.
Thursday night and Friday...
Showers look to be most widespread during this period. The timing
of various weather features will be crucial to the actual outcome.
Latest run of the GFS has much more amplified mid level trough
than the ECMWF. Thus, the GFS brings a potentially subtropical or
tropical low much closer to our region than the ECMWF. In
addition, a low pressure is forecast to move through the Great
Lakes into Quebec. Just about all of the models try to establish
some form of energy transfer, and develop a secondary low pressure
somewhere of the Mid Atlantic coast.
Were this to occur, our region would be more likely to get a
soaking rain, if this secondary low pressure gets close enough.
This is where the timing of all the major weather features will
come into play. If the mid level trough is more like the ECMWF
solution, then most of the moisture plume stays off to our east. A
solution more like the GFS gets us some much-needed rain.
At this time, only have moderate confidence in this portion of the
forecast. We`re still a day or two away from getting better
sampling of the shortwave energy which will ultimately amplify the
mid level longwave trough over the eastern USA. Will just have to
wait a bit more until this happens to have a better idea on the
likely outcome.
Saturday into Monday...
Risk for showers may linger into a portion of Saturday. However,
upper air pattern is progressive, so trend will be for drier and
cooler weather later this weekend. Cooler weather persists into
Monday, with below normal temperatures.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Tuesday Night/...
Tonight...Moderate confidence. Mainly VFR. Patchy MVFR cigs and
sct showers possible across northern MA overnight. Patchy MVFR/IFR
vsbys and cigs possible toward the south coast. Low confidence in
IFR.
Tuesday...Moderate to high confidence. VFR. Increasing SW winds
with gusts 25 knots in the afternoon.
Tuesday night...Moderate to high confidence. VFR. Diminishing
wind. Areas of IFR cigs/vsbys in developing fog overnight.
Outlook /Wednesday through Saturday/...
Wednesday...Any lingering MVFR conditions in patchy fog lifts to
a SCT-BKN VFR deck. Dry weather prevails.
Thursday and Friday...VFR likely to start but then lowering to
MVFR or IFR with a risk of rain. High confidence in trends, but
low confidence in details.
Saturday...Becoming drier. Mainly MVFR to IFR during the day, with
slow improvement to VFR Saturday night. Low confidence in timing.
&&
.MARINE...
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Tuesday Night/...High confidence.
Tonight...
A cold front will likely stall across the waters and southern New
England this evening. This front will slowly return north as a
warm front late tonight. Winds will remain light much of the
night. A 3-4 foot east swell will continue on the eastern waters.
A Small Craft Advisory continues on these eastern waters for the
combined seas.
Tuesday...
As the front moves to the north Tuesday, winds will pick up out
of the southwest, with gusts 25 to 30 knots by Tuesday afternoon.
These will slowly diminish in the evening. A 3-foot east swell
will linger on the eastern waters through the day.
A Small Craft Advisory will be in effect on most waters for both
winds and seas.
Tuesday night...
Diminishing winds, but seas linger at 5-6 feet. Small Craft
advisory may be needed for some of the waters.
Outlook /Wednesday through Saturday/...
Wed...winds diminish as a weakening cold front sags into the
region during the night. Thus, seas will subside as well. Dry
weather and good vsby, although risk of patchy fog toward Thu
morning.
Thu...onshore winds as a low pres enters PA and NY state. Low
risk for showers and areas of fog.
Friday into Saturday...This is a complicated period, which will
be dominated by the exact track and strength of a potentially
subtropical or tropical low off the East Coast of the USA.
Expecting increasing E to SE winds Friday, which will start to
build seas. Eventually, these winds turn N to NW Friday night into
Saturday. Low confidence in the timing, but moderate confidence in
the trend.
While expecting rough seas to develop, mainly due to large
southeast swell, we may be underforecasting them at this point.
Should the aforementioned low off the East Coast get closer to our
region than currently forecast, wind waves would also be
increased, resulting in higher significant wave heights.
Mariners should pay close attention to the forecast during the
course of this week, and adjust their plans, as needed.
&&
.CLIMATE...
Record High Temperatures:
Tuesday October 18th Wednesday October 19th
Boston 82 in 1947 Boston 84 in 1945
Worcester 85 in 1908 Worcester 81 in 1963
Providence 85 in 1908 Providence 81 in 1945
Hartford 80 in 1968 Hartford 82 in 1963
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from noon to 8 PM EDT Tuesday for
ANZ232>237-255-256.
Small Craft Advisory until 8 PM EDT Tuesday for ANZ250-254.
&&
$$
SYNOPSIS...WTB/Belk
NEAR TERM...KJC
SHORT TERM...WTB
LONG TERM...Belk
AVIATION...WTB/Belk
MARINE...WTB/Belk
CLIMATE...
Area Forecast Discussion
National Weather Service Gray ME
932 PM EDT Mon Oct 17 2016
.SYNOPSIS...
A warm front will lift northeast through the region tonight.
Temperatures will be very warm south of the warm front on Tuesday,
but north of the front it will be cooler with showers expected. As
low pressure moves through Quebec, it will drag a cold front into
New England Tuesday night. This front will linger offshore before
lifting back north as a warm front Thursday into Thursday night
with more showers possible. Low pressure tracking through the
Great Lakes will bring another cold front toward the area Friday
into Friday night, more showers possible ahead of it.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
930 PM Update...Have adjusted PoPs a little bit for the overnight
hours, mainly across southwestern NH. This due to a dying MCS that
should bring some light measurable rain to that region in a few
hours. There probably won`t be any thunder in the CWA with this,
but cannot rule out an isolated rumble. Otherwise, WAA showers
will be possible later on tonight across the rest of the region as
the warm frontal boundary above the boundary layer lifts
northward.
Otherwise, backdoor cold front continues to push southward and has
cleared maine and should move southward across southern NH over
the next couple of hours. Have adjusted overnight temperatures
based on latest trends in observational data, with temperatures
already in the lower 40s in the western ME mountains. Temperatures
across southern NH on Tuesday will be tricky and will hinge on
how stubborn the SFC warm front is when it attempts to return
northward. Haven`t changed current forecast temps for Tuesday, but
there is considerable bust potential with 20 degree errors
possible in some spots.
6 PM Update...Very minor adjustments to the going forecast based
on latest trends in radar/satellite and other observational data.
The pleasant evening will continue for most...with showers
expected to arrive in the western zones around midnight. MCS over
Lake Ontario as of 22z will most likely weaken significantly and
perhaps fall apart before making it as far east as the CT river
valley. A few showers may survive and if they do would affect
western NH around midnight give or take an hour.
Previously...
For tonight will see increasing warm air advection bring mid to
high clouds into the region this evening, with potential lower
stratus developing closer to the coast as Tds and temps come
together. Watching cluster of convection currently moving across
Ontario, which is associated with 850mb speed max and tightening
thermal gradient. Nam12 keeps bulk of precip N of the CWA, while
18Z HRRR is pushing convection further S into NH and ME, but
weakening /although previous runs kept it stronger as it moved
into NH. This will be the rain maker as it moves along the front
late tonight into early Tuesday...if it holds together northern
and western zones could see a quarter to half inch, and some
possible thunder, if not, most areas will be limited to a quarter
of an inch or less. lows should drop off enough early to bring the
mountains down into the mid to upper 40s, and everywhere else into
the 50s, but the temp fall will slow a great deal after midnight.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Models have been fairly persistent with keeping the cooler in
place in all but srn NH and Ct vly as pseudo cold air damming
situation with SE flow holding back the warm air in all but York
county ME through most of the day. So highs will vary quite a bit,
reaching well into the 70s in the souther tier of NH counties and
into the low to mid 70s in the CT valley, perhaps as far north as
KHIE. These areas will break into partly to mostly skies in the
afternoon. The question is how far on the coastal plain can the
warm air make make it before sunset. Will hold the areas to highs
around 60, with interior foothill and mountain areas in western
ME limited to the mid-upper 50s. Any morning showers should end
across all but FRanklin and somerset counties, where some
dynamics could persist into the afternoon.
Cold front will approach from the west Tue evening and will
increase the chance of showers in the N and W, but will likely
weaken as they head toward the coast, and should the htreat of any
SHRA diminish after midnight. Lows will be balmy for the third
week of October, generally in the mid 50s to low 60s.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
High pressure builds into the area from the west on Wednesday with
another day of warm temperatures expected. Highs for most of the
area will be in the 70s, with a few 80s possible in southern New
Hampshire. Increased moisture will also keep nighttime lows much
above normal.
A large upper level trough sharpens over the western Great Lakes
and Mississippi Valley on Thursday which will drive cyclogenesis
over the eastern Great Lakes. Expect an onshore easterly flow over
northern New England on Thursday and an increasing chance of
showers as a warm front sharpens to our south. This warm front
will lift north into Canada Thursday night into Friday morning
while the surface low tracks through the Saint Lawrence Valley or
upstate New York. Models disagree on how sharp the upper trough
will be and as a result disagree on the resulting track of the
surface low, but there is broad agreement that there will be a
period of rain beginning on Thursday and lasting through at least
Friday night. Both the GFS and ECMWF pull in moisture from a weak
tropical low off the east coast as well, which could help produce
heavy rain somewhere, but where that may be will depend on the
track.
The core of the upper trough moves into the Northeast on Saturday
and lingers through the weekend. This will bring cooler
temperatures and a good deal of cloud cover through the weekend.
The GFS maintains a threat of showers through the whole weekend as
its upper low drags through while the ECMWF is drier and colder.
It is possible that the remaining areas which haven`t frozen yet
could see their first freeze late this weekend or early next week.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Short Term...low clouds develop well after midnight, and IFR
conditions expected toward daybreak and lingering through most of
Tue morning. KMHT/KLEB/KHIE should improve to VFR in the
afternoon, with MVFR lingering elsewhere through the evening.
Could see improvement to VFR late Tuesday night after cold front
passes.
Long Term...Should see mostly VFR conditions Wednesday, but
conditions deteriorate Thursday in an onshore flow with increasing
clouds and showers. IFR or LIFR conditions are possible Thursday
through Friday night. Could see an improvement to VFR this
weekend.
&&
.MARINE...
Short Term...SCA issued for increasing SW flow ahead of a cold
front Tuesday afternoon through Tue evening. Winds seas will
diminish late Tue night.
Long Term...A frontal boundary which moves into the Gulf of Maine
late Tuesday night will linger just outside the Gulf of Maine
before pushing back north as a warm front Thursday into Thursday
night. It is possible that southerly flow behind the warm front
and ahead of the advancing cold front could bring wind gusts to 25
KT over the waters on Friday. Winds behind the cold front may be a
bit stronger Friday night into Saturday though the timing is still
uncertain.
&&
.TIDES/COASTAL FLOODING...
We`re currently in the period of high astronomical tides.
High tides of note are referenced to the Portland Harbor tide gage
where flood stage is 12 ft mllw. It won`t take much onshore wind
or wave action to cause issues along the coast and the situation will
be watched closely through late this week.
In particular...in the strengthening southeasterly flow on
Tuesday could bring Portland to just above the 12 ft flood
stage...so worth watching as some uncertainty exists with the
wind forecast.
1251 AM Tue 11.0 ft mllw
108 PM Tue 11.7 ft mllw
200 PM Wed 11.5 ft mllw
256 PM Thu 11.1 ft mllw
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory from 2 PM Tuesday to 8 AM EDT Wednesday
for ANZ150>152-154.
&&
$$
NEAR TERM UPDATE...Ekster
Area Forecast Discussion
National Weather Service Duluth MN
445 AM CDT TUE OCT 18 2016
.SHORT TERM...(Today through Wednesday)
Issued at 340 AM CDT Tue Oct 18 2016
A strong surface low was over far eastern Lake Superior this
morning, with a cold front draped to it`s southwest across upper
Michigan and Wisconsin to Iowa. Aloft, A shortwave was moving out
of Minnesota and into Wisconsin, driving much of the convection
currently over upper Michigan and northeast Wisconsin. These
storms are also moving along a mid level trough axis/baroclinic
zone which is draped from northern Iowa northeast through
Wisconsin to upper Michigan. These features are keeping all the
current convection to northeast Wisconsin and upper Michigan this
morning, with only some showers over northwest Wisconsin. During
the day today this low pressure system is going to continue to
move east, with diminishing potential for precipitation across the
forecast area this morning. Northwest flow and mostly cloudy skies
in the upper level cyclonic flow aloft will keep our temperatures
cool, with highs only in the 50s to around 60. A weak shortwave
that is currently over northern Montana/southern Saskatchewan and
producing some showers will slowly slide our direction today and
tonight, and should bring a small chance of showers to the
forecast area tonight. With the upper level flow remaining
northwest and cyclonic in nature, expect partly to mostly cloudy
skies to continue. This should also keep our temperatures from
dropping too far tonight, and have lows in the 30s and low 40s.
Some spots may get colder if they clear out. Wednesday will also
be cool as the northwest flow continues, and with enough cold air
aloft to keep even mixing from warming us up very much. Highs
should only get into the mid-upper 40s and 50s.
.LONG TERM...(Wednesday night through Monday)
Issued at 340 AM CDT Tue Oct 18 2016
The main concerns for the long term involve small chances of rain,
possibly mixing with snow, associated with several subtle
disturbances moving through the Northland through the middle of next
week.
A cutoff low is forecast over far northern Ontario and another
trough of low pressure will be found over the Central Plains
Wednesday evening. Quasi-zonal flow is expected in the mid-levels
with northwesterly breezes and cold air advection near the surface.
The southern stream trough and associated vort max will kick the
cutoff low east into Quebec by Thursday afternoon. At the same time
the shortwave trough will amplify the longwave pattern as it moves
into the Mississippi River Valley. Clouds are expected to increase
Wednesday night and Thursday as a ribbon of vorticity rotates
southeastward on the back side of the cutoff low. A few scattered
rain or snow showers are possible along the International Border
late overnight and early Thursday morning. Northwest to northerly
flow over western Lake Superior will raise the potential for lake
effect rain or snow showers for northern Bayfield County Wednesday
night and Thursday. With relatively warm air temperatures, there are
some concerns regarding parcel residence time and the amount of
moisture flux required to generate precipitation. A similar set of
forecast conditions occurred last week with no precipitation. Wind
speeds are somewhat light, as well. Should showers develop, they are
not expected to move inland by more than a few miles. Consensus
blends feature no precipitation, so added some low chance pops
generally north of US-2 in Bayfield County.
Beyond Thursday, confidence in the forecast diminishes. Significant
differences emerge in the GEFS members and in the deterministic
output from the GFS, ECMWF, and GEM. The GEM moves the trough
eastward through Saturday and eventually evolves a cutoff low over
Quebec Saturday night. Meanwhile, the GFS, GEFS members, and ECMWF
all feature a slower eastward progression and an earlier transition
into a cutoff low. Guidance also points to another shortwave trough
moving into the Canadian Prairies on Friday. The intensity of this
feature and timing are split between deterministic solutions, but
GEFS members are similar in their handling. The shortwave is
forecast to move through the Northland Friday night and Saturday
morning. Moisture seems lacking with a persistent west to northwest
flow ahead of the feature. Even so, there is a small chance of a
band of rain developing along and ahead of a warm front lifting
northward as the shortwave passes through. Opted to keep the
consensus blend for POPs Friday night and Saturday.
Model differences are much more pronounced Saturday night and Sunday.
The GFS bringing another potent shortwave and associated vort
max into the region, with a compact surface low advancing out of the
Dakotas and into the Northland by Sunday morning. ECMWF and GEM show
a more subtle feature and GEFS members are split with timing and
amplitude of the feature. Consensus yields a slight chance of rain
or snow showers in far northern Minnesota and a dry forecast
elsewhere Sunday and Sunday night. With poor agreement and overall
low confidence, saw no reason to deviate from consensus.
Sunday night through Monday night should see a ridge building across
the Rockies and into the Northern Plains. This should usher in a
period of quiet weather with zonal flow in the mid-levels and
southwest breezes near the surface.
Temperatures will start out near to slightly below normal for
Wednesday and Thursday, gradually warming to near to slightly above
normal for the remainder of the period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1231 AM CDT Tue Oct 18 2016
An area of low pressure had moved to the Upper Michigan between
Lake Michigan and Lake Superior as of late evening. A cold front
extended southwest out of this low all the way into Kansas. A
shortwave and FGEN continued to cause showers and a few
thunderstorms over northwest Wisconsin with just light rain
further northwest. The showers/storms will diminish then end
overnight as the FGEN, front, and low all move away from the
region. Conditions varied widely across the Northland, from mainly
VFR over northern Minnesota to IFR over parts of northern
Wisconsin. As clouds have thinned over northern Minnesota, some
fog has formed and we expect that to continue overnight. Fog was
also occurring along portions of Lake Superior, especially the
south shore. In addition to the fog, the RAP and HRRR both show
MVFR ceilings moving in from the northwest out of Canada. A look
at observations shows MVFR ceilings over southern Manitoba close
to what the RAP/HRRR have been indicating. We bring those ceilings
into KINL/KHIB/KDLH late tonight then improve conditions to VFR
through the day Tuesday.
Another shortwave trough will bring thickening clouds Tuesday
night and will lower ceilings late in the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 41 51 33 / 0 20 0 0
INL 51 35 43 32 / 0 0 0 10
BRD 59 40 51 33 / 0 20 0 0
HYR 60 43 56 35 / 0 0 0 0
ASX 60 43 54 36 / 10 10 0 0
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...LE
LONG TERM...Huyck
AVIATION...Melde
Area Forecast Discussion
National Weather Service Gray ME
354 AM EDT Tue Oct 18 2016
.SYNOPSIS...
A warm front will try to slowly lift northeast through the region
today. Temperatures will be very warm south of the warm front
today, but north of the front it will be cooler with showers
expected. As low pressure moves through Quebec, it will drag a
weak front into New England tonight and then move offshore. High
pressure with dry and very mild temperatures are expected
Wednesday. A trough of Low pressure will track across New England
Thursday and Friday and will bring some much needed rain to the
area. The system exits into the maritimes over the weekend with
breezy conditions and much cooler temperatures in its wake. Along
with the cool temperatures, clouds and even a few showers possible
in the mountains over the weekend.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
High Impact Weather Potential: Splashover/minor coastal flood
potential /see Tides/Coastal Flood section below/.
Current Pattern: A look at early morning water vapor imagery reveals
decaying area of enhanced moisture associated with earlier MCS whose
remnants are now exiting my southern zones. Shortwave ridging is
now arriving from the west with next area of deep moisture
associated with developing surface low pressure system over northern
Michigan. Down at the surface...we can see a high pressure ridge
axis aligned over eastern Maine with building SLPs in a cold air
damming pattern setting up over coastal Maine into southern NH.
South and west of this feature is a stationary boundary separating
yesterday/s warmth from cooler air draining south with the high.
With aforementioned low pressure system continuing to lift north
and east...and shortwave ridging moving east of our longitude...
developing deep layer southwesterly flow will begin to nudge the
surface front north and east ahead of an approaching cold front
that we/ll discuss in the tonight forecast. Thus...forecast
concerns center around 1-precipitation potential in the
strengthening WAA regime and 2-surface temperatures and how the
surface front evolves.
Through Daybreak: Backdoor front continues to push south and
west...having cleared southern NH with surface pressures continuing
to rise. Last remnants of decaying MCS will exit my southern NH
zones through 5am...with nothing more than a few sprinkles noted
north of this. Expect this trend to continue...with a few light
showers/sprinkles along the leading edge of the moisture surge at H8
continuing over northern areas through 8am. Temperatures come down
another few degrees under the light northeasterly flow...in the
upper 40s to mid 50s.
Today: Deep southwesterly flow overspreads the region today well
ahead of deep low pressure that will reach near James Bay early this
afternoon...continuing northeast into this evening. Warm front at
H8 will depart my Maine zones this AM...taking any remaining light
shower activity with it. With surface low pressure so far removed
to our north and west...the surface boundary will struggle to make
northward progress today...with most recent renditions of high
resolution guidance continuing to bring the warm air to a smaller
and smaller portion of our forecast area. Will not go all the way
to the HRRR which indicates that the warm front does not arrive
during the daylight hours...but will trend afternoon highs back some
from inherited forecast. This brings Cheshire/Hillsborough/
Rockingham counties into the lower 70s...with 60s north and east
of this except northern Oxford/Franklin/Somerset in Maine where
mid 50s will likely be it. Certainly some bust potential vicinity
LEB/CON/PSM/SFM...but growing confidence that the warm air fails
to reach even southern Maine today.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
High Impact Weather Potential: Minimal.
Pattern: Broad southwesterly flow will remain over the area through
the short term forecast period with just enough of an angle between
this flow and upstream surface front to push it through the region
tonight and offshore for Wednesday. Primary forecast concerns
center around precipitation potential along the front.
Tonight: Surface cold front will be just upstream of New England at
00Z...nearing the coastal plain by daybreak Wednesday. Llevel flow
largely veered ahead of the boundary with mid level shortwave energy
having bypassed the front to our north and east. Thus...while a +2-
3 sigma PWAT plume will pull overhead through the night...waning
instability and llevel convergence suggests a decaying band of
showers /embedded thunder?/ and forecast PoPs will follow this trend
with measurable precipitation rather unlikely along the coastal
plain. Clouds and warm airmass aloft will allow for another night
of mild low temperatures...with consensus lows in the 50s/lower 60s
looking good.
Wednesday: Nice day expected on Wednesday with high pressure
building in behind departing cold front. Deep moisture plume will
be pushed offshore during the day...with very modest cold advection
behind this feature. Could see some residual clouds in the
mountains under modest northwesterly flow...but mostly sunny south
south and east of this. T8s remain around +10C with T9s +12-17C
north to south during the afternoon. Thus...expect highs to be well
above normal...60s north of the mountains with mid/upper 70s in the
foothills and points south. Enjoy it...as significant changes are
in store in the long term period below!
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A progressive digging upper trough will move across the Ohio
Valley and Great Lakes region Thursday and in advance first
spreading clouds and then the chance of rain in the afternoon
from west to east. The upper trough will continue to develop over
the eastern Great Lakes Thursday night and Friday becoming
vertically stacked and spawning surface cyclogenesis across the
St Lawrence Valley and upstate New York. A broad area of rain
will gradually develop by Friday afternoon. The upper trough will
continue to develop as it becomes negatively tilted and then
becomes a closed low by Friday night. As the system develops,
models are indicating a strong southeast flow will develop to its
east and will likely pick up some tropical moisture from a system
off the southeast coast of the U.S. This may bring some soaking
rains to the area late Friday and Friday night.
Models indicate the closed upper low is expected to move slowly north
and east into the maritimes Saturday and Sunday possibly allowing
some lingering showers mainly in the mountains due to the unstable
cyclonic flow. Much cooler temperatures will arrive behind the
system Saturday into Sunday.
Cool and dry weather is expected Monday as Canadian high
pressure builds across the region.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
Short Term /through Wednesday/...
Summary: A front draped across the region today will bring
variable...but gradually deteriorating conditions...but will lift
north Tuesday evening with a weakening cold front moving through
the area tonight with high pressure and improving conditions building
in for Wednesday.
Restrictions: A few showers over southern NH as of this writing
with a few sprinkles/light showers over northern NH and portions
of western ME. Expect only isolated activity for the remainder of
the overnight with increasing onshore flow causing MVFR/IFR
restrictions to develop with ample llevel moisture fueling a
developing MVFR deck inland. Conditions will very gradually
improve to VFR on Tuesday afternoon...first over southern
NH...then spreading north and east...likely reaching AUG/RKD last
Tuesday night. Beyond this a decaying line of showers will arrive
Tuesday night with isolated restrictions LEB/HIE. Also...expect
additional fog development Tuesday night CON/HIE/LEB with VFR
conditions expected for the day Wednesday.
Winds: Calm/light-variable winds away from the coast...with
northeasterly winds 5-10kts along the coast gradually veering to
more southeasterly and southerly today 5-10kts. Winds will
continue to veer southwesterly tonight 5-10kts before shifting
northwest 10-15kts for the day on Wednesday.
LLWS: GYX VAD wind profile suggest northeasterly winds just off
the surface 30+kts at PWM/RKD and expect this to continue through
daybreak. Southerly winds strengthen aloft by late this evening
with 30-40kts in the 1-2kft layer with another period of LLWS
expected this evening.
Thunder: An isolated thunderstorm is possible overnight embedded
within isolated shower activity. Embedded thunder is also possible
with decaying line of showers that arrives tonight. No thunder
Wednesday.
Long Term...Conditions deteriorate Thursday in an onshore flow
with increasing clouds and showers. IFR or LIFR conditions are
possible Thursday through Friday night. Could see an improvement
to VFR this weekend.
&&
.MARINE...
Short Term...Winds nearing SCA levels this morning...but bona-fide
SCA conditions hold off until tonight with strengthening southerly
winds/building seas. Winds/seas diminish behind departing cold
front Wednesday.
Long Term...An increasing south to southeast flow Friday and
Friday night may develop SCA conditions. Winds behind the system
over the weekend may be gusty from the west and northwest so SCA
conditions may continue.
&&
.TIDES/COASTAL FLOODING...
Have issued coastal flood statement for this afternoon/s 1pm EDT
high tide given surge forecast of up to one half foot...which
would put both Portland and Fort Point right at FS early this
afternoon. Wave action does not look that impactful...only 2-3
feet at the coast. Will monitor the surge/winds this morning and
see if advisory is warranted.
Tides remain high for the next few days...but winds look to remain
light beyond today/s high tide. Will continue to monitor.
Tides at Portland the next few days follow below:
108 PM Tue 11.7 ft mllw
200 PM Wed 11.5 ft mllw
256 PM Thu 11.1 ft mllw
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory from 2 PM this afternoon to 8 AM EDT
Wednesday for ANZ150>152-154.
&&
$$
SYNOPSIS...Arnott/Marine
NEAR TERM...Arnott
SHORT TERM...Arnott
LONG TERM...Marine
AVIATION...Arnott
MARINE...Arnott/Marine
TIDES/COASTAL FLOODING...Arnott
AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
355 AM CDT Tue Oct 18 2016
.SHORT TERM...
Not much has changed across the region from yesterday. Upper level
ridge that was centered west of the region is now nearly overhead
this morning. At the surface, ridge of high pressure extends from
the western Atlantic across the southeastern United States.
Clockwise surface flow is maintaining upper 60 to 70 degree
dewpoints along with slowly increasing column moisture from the
bottom up as winds shift around to southward. Thus, precip water
value now topping 1.5". The 00z sounding from Monday shows a fairly
warm layer cap around 15kft, from upper ridge in place. This will
likely keep convective development limited in spatial coverage as
well as intensity. Latest radar imagery shows scattered showers in
the coastal waters trying to spread inland. The HRRR indicates that
this will take place in time, as daytime heating ensues.
Temperatures will continue to be unusually hot with high pressure in
place, so have kept forecast highs in the mid to upper 80s for the
next couple days. Low end rain chances to continue to be in the
forecast, but with a transition to more western portions of the
forecast area by Wednesday as the upper ridge slides east.
Light winds and increased moisture will aide in the development of
fog for the next couple days. The main deciding factor on how dense
the fog becomes will be low level cloud development. Should see a
rapid improvement in visibilities as the surface heats up quickly.
.LONG TERM...
Models are still showing the next significant weather impact to be a
cold front marching through the area Thursday afternoon and through
the overnight period. The initial wind shift looks to begin early
Thursday afternoon which is about 6 hours earlier than model runs
from 24 hrs ago. The GFS still shows more qpf than the ECMWF with
the frontal passage but has trended downward and closer to the more
typical events for this time of year. A significant drop in
temperatures is expected Friday through the weekend. 15-20 degree
drop in highs and lows are likely if model solutions don`t change
much between now and then.
Meffer
&&
.AVIATION...
Conditions are not expected to change much for this taf cycle. Fog
during the morning at most sites will dissipate by 9am and once
again tonight, fog should set back in for several terminals. TEMPO
groups should suffice for fog at the end of this 12z cycle. Low
ceilings will set in first and lower to the sfc late
tonight.
&&
.MARINE...
Models beginning to finally agree at least on timing of the cold
front moving through Thursnight. The 12z model run today should have
a better handle on temporal resolution and sensible weather. Will
keep forecast relatively similar to the current ongoing package.
Cold front slows as it approaches the coast but is not expected to
stall. Stronger forcing moves in behind the front causing it to move
rapidly through the coastal waters overnight and early Friday. Some
thunderstorm activity could accompany the front mainly over the open
gulf waters. Winds and seas will rise quickly behind the front and
could stay elevated into the weekend.
&&
DECISION SUPPORT...
DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.
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 87 68 86 66 / 10 10 20 10
BTR 88 70 87 68 / 10 10 20 10
ASD 86 69 86 67 / 20 10 10 10
MSY 86 72 86 71 / 20 10 10 10
GPT 83 70 84 69 / 20 0 10 10
PQL 85 68 85 65 / 10 0 10 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Dense Fog Advisory until 9 AM CDT this morning for LAZ034>037-
039-040-046>050-071-072.
GM...None.
MS...Dense Fog Advisory until 9 AM CDT this morning for MSZ068>071.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Marquette MI
448 AM EDT Tue Oct 18 2016
.SHORT TERM...(Today and tonight)
Issued at 446 AM EDT TUE OCT 18 2016
00Z raobs/latest wv imagery and RAP analysis show the shrtwv
responsible for the heavy ra/svr storms yday evng exiting to the ne
along the most sgnft showers/TS. The associated cold fnt on the sw
flank of deepening lo pres moving into se Ontario has sank to the s
of all but the far scentral cwa. Despite some deep lyr qvector dvgc
in the wake of this disturbance, some showers/a few TS linger along
a line fm scentrl MN acrs nw WI into central Upr MI ahead of another
shrtwv aprchg fm the wsw and under axis of h85-7 fgen behind the
cold fnt and where mucapes up to 500j/kg and steeper mid lvl lapse
rates up to 7C/km linger per spc mesoanalysis/00Z MPX raob.
Farther to the nw, the 00Z INL raob shows a much drier sfc-h5 lyr,
but a good deal of hier clds linger in the mstr aoa h5 shown on that
raob and on the cyc side of the shrtwv supporting the lingering
showers.
Main fcst concerns in the short term wl be on pops today and then
cld/temp trends as the drier llvl air shown on the 00Z INL raob
grdly slides into the area.
Today...Incrsg deep lyr h85-3 qvector dvgc in the wake of stronger
shrtwv exiting to the ne with deeper convection is fcst to dominate
Upr MI, so expect the line of showers stretching fm scentral MN into
wcentrl Upr MI to diminish with time and probably by mid mrng as
they shift to the ese under axis of h85-7 fgen in the wake of the
departing sfc cold fnt. Plan to carry some sct showers thru mid mrng
mainly over the scentral. There wl be some gusty nw winds mainly
this mrng over the ne cwa in the wake of the departing/deepening sfc
lo pres, but these winds should diminish during the aftn as the pres
gradient weakens with the closer aprch of sfc hi pres toward the Upr
MS River Valley. The arrival of the drier llvl air depicted on the
00Z INL roab/larger scale subsidence/more acyc llvl flow should
result in clrg thru the day. Since h85 temps wl fall to only 6-8C by
00Z Wed, expect another relatively warm day with max temps in the
50s to as hi as the mid 60s over the se with the downslope NW flow.
Tngt...While there are hints some clds wl move into at least the wrn
cwa late as a weak shrtwv/lo pres trof aprch fm the w, lingering
llvl dry air/acyc flow most of the ngt wl maintain dry wx thru 12Z
Wed.
.LONG TERM...(Wednesday through Monday)
Issued at 443 AM EDT TUE OCT 18 2016
Nam shows a 500 mb shortwave over WY and another over the Canadian
prairies 12z Wed. Both of these shortwaves move east and help dig a
deep trough over the central U.S. on Thu and Thu night. Looks pretty
quiet for this forecast period, but could still see some lake effect
pcpn starting on Thu as colder air comes into the area and across
Lake Superior. 850 mb temperatures fall to -3C to -5C on Thu and
with lake temperatures from 9C to 12C, this is enough lake-850 mb
delta-t for lake effect pcpn. Did add in some pops for this with low
chance pops in northwest and north lake effect pxpn belts for thu
and thu night. Did not make too many changes to the going forecast.
In the extended, GFS and ECMWF show a 500 mb ridge over the desert
sw with a deep trough over the central U.S. 12z Fri. This trough is
very deep with the GFS and broader with the ECMWF with 850 mb
temperatures down to -4C to -7C 12z Fri and this cold air remains
over Lake Superior through 12z Sat. A shortwave moves through Sat
night into Sun morning. A broad 500 mb ridge moves into the Rockies
with a trough over the ern U.S. 12z Mon. Temperatures look to be
below normal for the start of this forecast and then get to near
normal by the end of the forecast period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 125 AM EDT TUE OCT 18 2016
Lingering low level moisture along a warm front will keep lower
ceilings and visibility in place through tonight. A stronger low
pressure system will lift northeastward into the area and could
bring around of showers into the TAF sites, although it looks like
heaviest rain has moved east of the TAF sites. Conditions should
remain in the IFR to LIFR range through late tonight at all the TAF
sites although expect dry air to move on gusty w-nw winds late
tonight into Tue morning allowing for conditions to quickly improve
to VFR by late morning/early afternoon.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 446 AM EDT TUE OCT 18 2016
Cancelled previous gale warning in effect for the e half of Lake
Superior as lo pres exiting to the ne is not intensifying as quickly
as anticipated, resulting in weaker nw winds up to only 30 kts in
this area. Then expect winds to diminish to under 25 kts by this
aftn and remain at 20-25 kts or less through the rest of the week as
a relatively weak pressure gradient dominates.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...07
AVIATION...Voss
MARINE...KC
Area Forecast Discussion
National Weather Service Pueblo CO
1119 PM MDT Mon Oct 17 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 237 PM MDT Mon Oct 17 2016
...Critical Fire Weather conditions continuing into this evening...
Strong winds and critical fire weather conditions will continue
across the district this evening until winds decouple and/or the
arrival of a cold front brings slightly higher humidity levels into
eastern portions of the area. The cold front is evident in latest
radar loops across northeast El Paso county extending eastward
across northern Kiowa county. HRRR seems to be a little slow with
its progression westward and southward. Front should move through
most of the southeast plains by 04z. This will shift winds out of
the northeast to east across the plains with the front banking up
along the east slopes of the southeast mountains overnight.
Meanwhile...winds across the mountains have already started to
decrease below high wind criteria as the mountain wave has broken
down. Its will remain windy through 6 PM due to deep mixing though
think the gusts in the 60 to 70 mph range will stay confined to the
highest peaks. Gusts in the 40 to 50 mph will continue for the lower
eastern slope regions until 6 PM...but should gradually decrease
after that. Have taken down the high wind warning as damaging wind
gusts in excess of 75 mph are no longer expected. Will leave the Red
Flag warning up until 9 PM...though suspect that eastern portions of
the area may be able to be cancelled earlier as humidities come up
behind the front.
For tomorrow...temperatures will be quite a bit cooler across the
area...with readings down around climatological normals. Winds
across the southeast plains and lower eastern slopes of the
southeast mountains will be lighter tomorrow...though gusty winds
will likely resurface across the mountains and interior valleys once
again. However with the cooler temperatures expected...humidity
levels should stay above the 15 percent critical threshold for Fire
Weather concerns. -KT
.LONG TERM...(Tuesday night through Monday)
Issued at 237 PM MDT Mon Oct 17 2016
...Very dry conditions continue...
Extended forecast looks pretty quiet. Cooler conditions through mid
week, followed by gradual warming as high pressure builds strongly
over the W US.
Any chance of precip for our area will come Tue night, as a trough
moves through N CO. Precip will be confined to Mts of Lake and
Chaffee County. Could see an inch or so over the Dvd by Wed morning
before things rapidly clear out behind the system Wed morning.
Cannot rule out some snowflakes over the Pikes Peak region, but
probability is low so will keep POPs silent outside the Central Mts.
Main impact will be continued cooling, with highs Wed closer to
average, or in the 60s over the Plains and 50s high valleys.
Beyond Wed, a broad ridge will strengthen and build from the west,
resulting in decreasing winds and increasing temps across our
area. Could see highs once again around 80 degrees for the Plains
by the weekend, and this warm spell will persist through Monday.
next chance of any precip for our area will not come until the day 8-
10 period, as a new W Coast trough begins to move into the Rockies.
Rose
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1119 PM MDT Mon Oct 17 2016
Other than some gusty winds...primarily during the afternoon hours
as well as the possibility of some smoke at times from the
Junkins wildfire located to the west-southwest of
Pueblo...anticipate that VFR conditions will continue over the
KALS...KCOS taf KPUB sites during the next 24 hours.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
400 AM EDT TUE OCT 18 2016
.SYNOPSIS...
High pressure at the surface and ridging aloft will keep conditions
warm and dry for the next few days, before a frontal system
approaches for the end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 300 AM Tuesday...
Fog may be a problem this morning but compared to previous days
forecast soundings look a little drier at the surface and dewpoint
depressions are generally larger. If fog were to occur it would most
likely be in the east. HRRR, SREF, and RAP solutions are not bullish
on fog so have kept it out of the TAFs at this time and will adjust
as needed.
Another warm day is expected and persistence suggests temperatures
climbing into the low to mid 80s by this afternoon as high pressure
continues at the surface with ridging aloft. Southwesterly return
flow around the back side of the surface high will help to bring a
little warm air advection to the area. No precipitation is expected
and clouds should be at a minimum, thus helping insolation bring
those afternoon highs up. Low temperatures in the upper 50s.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 300 AM Tuesday...
Wednesday will most likely be the warmest day of the week as high
pressure continues to dominate the surface pattern. Thicknesses
suggest high temperatures topping out in the mid 80s which for GSO
is near record levels but we could end up just below on the day.
Light southerly flow will again prevail with little cloud cover. Low
temperatures in the low 60s.
&&
.LONG TERM /Thursday through Monday/...
As of 355 AM Tuesday...
Thu: Another warm day, falling a few degrees short of daily records.
We`ll remain in a mild prefrontal air mass with a deep but narrowing
and weakening high pressure ridge spanning the area SW to NE. Expect
plenty of sunshine with a continued dry column, stable through a
deep layer, and no opportunity for moisture return. Projected
thicknesses get warmer with each set of model runs; a few days ago,
thickness forecasts for Thu were 20-25 m above normal, and now they
reach to around 35 m above normal, suggesting highs in the lower-mid
80s.
Thu night-Sat night: The potential remains for tropical or
subtropical low development between the Bahamas and Bermuda by mid
week, although the consensus of model solutions keeps this low
tracking roughly northward well off the Carolina coast Thu through
Fri. The cold front is expected to be aligned along the central/
southern Appalachians at 12z Fri morning, although if the GEFS/ECMWF
ensemble mean/SREF mean (a bit slower than op GFS/ECMWF) are
correct, this could be a little fast. But with substantial energy
diving into the trough base, it is apt to stay progressive, with the
surface cold front sweeping through central NC during the day Fri.
Moisture return remains scant along and ahead of the front, with
moisture fairly shallow and fleeting. Best forcing for ascent
including mid level DPVA and upper divergence will be focused to our
W and N, over western NC into VA, and will stay with the best pops
here, with lower chances across the south. QPF appears small given
the modest PW and shallow moisture. Expect highs Fri from the upper
60s NW to mid 70s SE. Thicknesses take their deepest plunge late Fri
into Fri night, bottoming out 30-35 m below normal. Will stay close
to guidance with highs in the lower-mid 60s, although if thicknesses
do indeed drop this low with a steady cool NW breeze, later
forecasts may need to bump these highs down a category. Lows will be
in the upper 40s west/lower 50s east Fri night, and solidly in the
lower to mid 40s Sat night.
Sun-Mon: Fair and cool but with moderating temps back near normal.
the mid level trough axis will kick farther to our NE with rising
heights aloft, while modified high pressure at the surface builds
across the Gulf states and Southeast. Highs 65-70 Sun and 69-73 Mon
with mostly sunny skies. -GIH
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
As of 130 AM Tuesday...
24 Hour TAF period: Fog will once again be the primary concern this
morning although less confidence in it happening this morning as
compared to previous days. Short term models are not showing much in
the way of fog development and forecast soundings are drier at the
surface then they have been the last few days. Dewpoint depressions
in the observations are also larger than they have been but if fog
were to occur it would be at KRWI or KFAY. Otherwise another day of
light southwesterly winds with no precipitation and mostly clear
skies.
Long term: VFR conditions are largely expected through Friday or so
when the next frontal system will approach from the west and bring a
chance for sub-VFR aviation conditions.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Ellis
NEAR TERM...Ellis
SHORT TERM...Ellis
LONG TERM...Hartfield
AVIATION...Ellis
Area Forecast Discussion
National Weather Service State College PA
1031 AM EDT Tue Oct 18 2016
.SYNOPSIS...
Southwest flow ahead of a cold front will keep much above normal
temperatures over the region right through midweek. Cooler air will
follow the cold frontal passage Wednesday. Unsettled conditions
will redevelop for the end of the week as a series of low pressure
areas ripple up along the trailing cold front. Breezy and colder
weather will move in for the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Another very warm day in progress with maxes topping 80F across
much of central and southern PA. See the Climo section below for
some of the records.
A sfc cold front will be approaching the eastern Gr Lakes by
nightfall which could threaten a shower into my NWRN zones before
the day is over, but in most places it will be a very warm and dry
day. HRRR suggests we should easily mix to at least 850 supporting
highs exceeding 70 over the north, and reaching at least the mid
80s over southern areas. With dewpoints nudging 60, it will even
feel a little humid.
The cold front will sag south overnight. Near term guidance is in
good agreement with the front washing and the area of showers
dwindling as it moves out of NWRN Pa down toward the coastal
plain. With the increase in cloudcover, lows will likely be even
warmer than tonight ranging from the mid 50s to mid 60s north to
south.
&&
.SHORT TERM /WEDNESDAY/...
Wednesday will still be very mild with almost no push of cooler
air behind the diffuse-dying cold front. A blend of models support
the potential for a stray shower over western and southern areas.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The trailing cold front is made to become the center of weather
attention for Thursday and Friday as a storm system or a series
of waves along the front organize over the southern Ohio Valley
and slide up through central Pa. The exact track of the low will
determine where the best rain will fall with a steady moderate to
heavy rain expected along and just behind the front, and a more
showery precipitation expected in the warm sector east of the
front. Right now the GEFS/GFS and ECMWF all show a track through
central Pa which would favor the NWRN half or so of my forecast
area for an inch or more of rain.
The upper trough will sharpen markedly as it drops through the
eastern Gr Lakes and closes off over NY before tracking into New
England and eastern Canada. A cooler blustery NW flow will develop
in its wake with scattered showers, especially over the higher
elevations of the west and north, a pattern we will see many times
over the upcoming cold weather months.
By Saturday morning it could be cold enough over the far NW for
some wet snowflakes to mix with the rain showers. Saturday night
into Sunday morning will be cooler still with a better chance of
rain or wet snow showers. No accumulations are expected.
For the last part of the weekend into early next week we should
see colder and mainly dry west/northwest flow. Deterministic GFS
differs from the ECMWF by showing a weak clipper type shortwave
bringing a chance of precip back into northern Pa by Sunday
night. The GEFS doesn`t support this. I used the blended MOS to
arrive at a very small chance of showers, but confidence is low.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR conds will last through this afternoon as SW flow increases
ahead of an approaching cold front. Winds will increase to around
10 mph (with gusts to 14-18 mph mainly across the west).
A cold front nears this evening, showers and cig restrictions
will work into the NW mtns. As front washes out over the central
mtns heading into Wed, MVFR cig restrictions and a few stray
showers will be poss - mainly the first half of the day.
Unsettled weather will impact the area late week into the weekend.
Outlook...
Tonight...Reductions NW half with chance of showers.
Wed...Reductions NW half and potentially into central mtns.
Thu-Fri...Reductions likely areawide. Sct showers SE, period of
rain elsewhere.
Sat...Restrictions NW. Sct showers NW. Breezy.
&&
.CLIMATE...
Daily record maximum temperatures are in jeopardy for 10/18. Here
are the current records:
Harrisburg: 82 in 1908
Williamsport: 82 in 1964
Altoona: 81 in 1998
Bradford: 75 in 1963
State College: 83 in 1938*
*10/18 high will be officially recorded on 10/19 (7am-7am COOP)
report so used 10/19 for record purposes.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...DeVoir/La Corte
SHORT TERM...La Corte
LONG TERM...La Corte
AVIATION...DeVoir/RXR
CLIMATE...
Area Forecast Discussion
National Weather Service Gray ME
1025 AM EDT Tue Oct 18 2016
.SYNOPSIS...
A warm front will try to slowly lift northeast through the region
today. Temperatures will be very warm south of the warm front
today, but north of the front it will be cooler with showers
expected. As low pressure moves through Quebec, it will drag a
weak front into New England tonight and then move offshore. High
pressure with dry and very mild temperatures are expected
Wednesday. A trough of Low pressure will track across New England
Thursday and Friday and will bring some much needed rain to the
area. The system exits into the maritimes over the weekend with
breezy conditions and much cooler temperatures in its wake. Along
with the cool temperatures, clouds and even a few showers possible
in the mountains over the weekend.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1020 AM...Winds have been more NE than SE this morning and this
allowing for stronger cold air damming to hold. Have adjusted sky
and temps to hold onto the clouds and cooler air longer across
the southern zones, and tweak maxes down in this areas as well.
Meso models do want to break the inversion in southern NH, the CT
valley and SW ME, but it will likely not happen until early to mid
afternoon, so highs will be limited to the mid to upper 60s in
many spots, with a few spots in the CT valley and maybe the
Merrimack valley making it to 70 or so. Also added patchy FG/DZ
to the coastal zones and the coastal plain of ME as the will see
more in the way of warm moisture advection above the inversion
here.
630 AM Update: Only minor changes needed this hour with
shower activity essentially over as we find ourselves in a void
between activity north of the international border and more
showers off the Massachusetts coast...with H8 warm front moving
overhead with just a sprinkle or two. Adjusted to current
temperatures/dewpoints with very minor PoP tweaks...primarily to
lower them in the near term.
Previous discussion below...
High Impact Weather Potential: Splashover/minor coastal flood
potential /see Tides/Coastal Flood section below/.
Current Pattern: A look at early morning water vapor imagery reveals
decaying area of enhanced moisture associated with earlier MCS whose
remnants are now exiting my southern zones. Shortwave ridging is
now arriving from the west with next area of deep moisture
associated with developing surface low pressure system over northern
Michigan. Down at the surface...we can see a high pressure ridge
axis aligned over eastern Maine with building SLPs in a cold air
damming pattern setting up over coastal Maine into southern NH.
South and west of this feature is a stationary boundary separating
yesterday/s warmth from cooler air draining south with the high.
With aforementioned low pressure system continuing to lift north
and east...and shortwave ridging moving east of our longitude...
developing deep layer southwesterly flow will begin to nudge the
surface front north and east ahead of an approaching cold front
that we/ll discuss in the tonight forecast. Thus...forecast
concerns center around 1-precipitation potential in the
strengthening WAA regime and 2-surface temperatures and how the
surface front evolves.
Through Daybreak: Backdoor front continues to push south and
west...having cleared southern NH with surface pressures continuing
to rise. Last remnants of decaying MCS will exit my southern NH
zones through 5am...with nothing more than a few sprinkles noted
north of this. Expect this trend to continue...with a few light
showers/sprinkles along the leading edge of the moisture surge at H8
continuing over northern areas through 8am. Temperatures come down
another few degrees under the light northeasterly flow...in the
upper 40s to mid 50s.
Today: Deep southwesterly flow overspreads the region today well
ahead of deep low pressure that will reach near James Bay early this
afternoon...continuing northeast into this evening. Warm front at
H8 will depart my Maine zones this AM...taking any remaining light
shower activity with it. With surface low pressure so far removed
to our north and west...the surface boundary will struggle to make
northward progress today...with most recent renditions of high
resolution guidance continuing to bring the warm air to a smaller
and smaller portion of our forecast area. Will not go all the way
to the HRRR which indicates that the warm front does not arrive
during the daylight hours...but will trend afternoon highs back some
from inherited forecast. This brings Cheshire/Hillsborough/
Rockingham counties into the lower 70s...with 60s north and east
of this except northern Oxford/Franklin/Somerset in Maine where
mid 50s will likely be it. Certainly some bust potential vicinity
LEB/CON/PSM/SFM...but growing confidence that the warm air fails
to reach even southern Maine today.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
High Impact Weather Potential: Minimal.
Pattern: Broad southwesterly flow will remain over the area through
the short term forecast period with just enough of an angle between
this flow and upstream surface front to push it through the region
tonight and offshore for Wednesday. Primary forecast concerns
center around precipitation potential along the front.
Tonight: Surface cold front will be just upstream of New England at
00Z...nearing the coastal plain by daybreak Wednesday. Llevel flow
largely veered ahead of the boundary with mid level shortwave energy
having bypassed the front to our north and east. Thus...while a +2-
3 sigma PWAT plume will pull overhead through the night...waning
instability and llevel convergence suggests a decaying band of
showers /embedded thunder?/ and forecast PoPs will follow this trend
with measurable precipitation rather unlikely along the coastal
plain. Clouds and warm airmass aloft will allow for another night
of mild low temperatures...with consensus lows in the 50s/lower 60s
looking good.
Wednesday: Nice day expected on Wednesday with high pressure
building in behind departing cold front. Deep moisture plume will
be pushed offshore during the day...with very modest cold advection
behind this feature. Could see some residual clouds in the
mountains under modest northwesterly flow...but mostly sunny south
south and east of this. T8s remain around +10C with T9s +12-17C
north to south during the afternoon. Thus...expect highs to be well
above normal...60s north of the mountains with mid/upper 70s in the
foothills and points south. Enjoy it...as significant changes are
in store in the long term period below!
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A progressive digging upper trough will move across the Ohio
Valley and Great Lakes region Thursday and in advance first
spreading clouds and then the chance of rain in the afternoon
from west to east. The upper trough will continue to develop over
the eastern Great Lakes Thursday night and Friday becoming
vertically stacked and spawning surface cyclogenesis across the
St Lawrence Valley and upstate New York. A broad area of rain
will gradually develop by Friday afternoon. The upper trough will
continue to develop as it becomes negatively tilted and then
becomes a closed low by Friday night. As the system develops,
models are indicating a strong southeast flow will develop to its
east and will likely pick up some tropical moisture from a system
off the southeast coast of the U.S. This may bring some soaking
rains to the area late Friday and Friday night.
Models indicate the closed upper low is expected to move slowly north
and east into the maritimes Saturday and Sunday possibly allowing
some lingering showers mainly in the mountains due to the unstable
cyclonic flow. Much cooler temperatures will arrive behind the
system Saturday into Sunday.
Cool and dry weather is expected Monday as Canadian high
pressure builds across the region.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
Short Term /through Wednesday/...
Summary: A warm front will slowly lift north through the area today
before a cold front moves in from the northwest tonight with high
pressure arriving for the day on Wednesday.
Restrictions: Conditions deteriorating attm with MVFR /and some
IFR/ cigs developing north of warm front. This trend will continue
through the morning before gradual improvement this afternoon and
evening. A few isolated showers are possible for ME terminals this
morning with dry conditions this afternoon. Tonight...a band of
showers will impact HIE/LEB before falling apart as it moves south
and east. Conditions overnight generally VFR except fog
development HIE/LEB and potentially CON/AUG. VFR for the day
Wednesday.
Winds: Generally from the northeast 5-10kts today...shifting
south 10 kts this afternoon into this evening as the warm front
moves north. Southwesterly winds shift northwesterly for the day
on Wednesday 10-15kts.
LLWS: Impressive LLWS setup this evening as southwesterly flow
strengthens atop strong llevel inversion. Expecting 30-40kt winds
at 1-2kft all sites through the overnight.
Thunder: Very remote chance of a rumble this evening
HIE/LEB...otherwise no threat.
Long Term...Conditions deteriorate Thursday in an onshore flow
with increasing clouds and showers. IFR or LIFR conditions are
possible Thursday through Friday night. Could see an improvement
to VFR this weekend.
&&
.MARINE...
Short Term...Winds nearing SCA levels this morning...but bona-fide
SCA conditions hold off until tonight with strengthening southerly
winds/building seas. Winds/seas diminish behind departing cold
front Wednesday.
Long Term...An increasing south to southeast flow Friday and
Friday night may develop SCA conditions. Winds behind the system
over the weekend may be gusty from the west and northwest so SCA
conditions may continue.
&&
.TIDES/COASTAL FLOODING...
Have issued coastal flood statement for this afternoon/s 1pm EDT
high tide given surge forecast of up to one half foot...which
would put both Portland and Fort Point right at FS early this
afternoon. Wave action does not look that impactful...only 2-3
feet at the coast. Will monitor the surge/winds this morning and
see if advisory is warranted.
Tides remain high for the next few days...but winds look to remain
light beyond today/s high tide. Will continue to monitor.
Tides at Portland the next few days follow below:
108 PM Tue 11.7 ft mllw
200 PM Wed 11.5 ft mllw
256 PM Thu 11.1 ft mllw
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ150>152-
154.
&&
$$
SYNOPSIS...Arnott/Marine
NEAR TERM...Arnott/Cempa
SHORT TERM...Arnott
LONG TERM...Marine
AVIATION...Arnott
MARINE...Arnott/Marine
TIDES/COASTAL FLOODING...
Area Forecast Discussion...UPDATED
National Weather Service New Orleans LA
951 AM CDT Tue Oct 18 2016
.UPDATE...
Sending a new zfp package to remove dense fog advisory headlines.
no other changes at this time. convergence banded showers in a
narrow line from Barataria Bay through Slidell may persist for
better part of the day, but should remain limited in areal
impacts, primarily fast moving showers, and handled with ongoing
PoPs. 24/RR
&&
.PREV DISCUSSION... /issued 747 AM CDT Tue Oct 18 2016/
..SOUNDING DISCUSSION...
The profile is saturated this morning at low levels with a
tropical airmass in place. That is enough for PW to be above
average at 1.6 inches. Spot showers are in the 15 kt southerly
onshore flow to 780 mb. From there winds switch to easterly in a
broad elevated subsidence inversion centered near 700 mb and the
air is much drier aloft. The strong inversion will prevent storms
today though isolated showers are likely to continue near coastal
areas given the ample moisture below the cap.
Krautmann
PREV DISCUSSION... /issued 355 AM CDT Tue Oct 18 2016/
SHORT TERM...
Not much has changed across the region from yesterday. Upper level
ridge that was centered west of the region is now nearly overhead
this morning. At the surface, ridge of high pressure extends from
the western Atlantic across the southeastern United States.
Clockwise surface flow is maintaining upper 60 to 70 degree
dewpoints along with slowly increasing column moisture from the
bottom up as winds shift around to southward. Thus, precip water
value now topping 1.5". The 00z sounding from Monday shows a fairly
warm layer cap around 15kft, from upper ridge in place. This will
likely keep convective development limited in spatial coverage as
well as intensity. Latest radar imagery shows scattered showers in
the coastal waters trying to spread inland. The HRRR indicates that
this will take place in time, as daytime heating ensues.
Temperatures will continue to be unusually hot with high pressure in
place, so have kept forecast highs in the mid to upper 80s for the
next couple days. Low end rain chances to continue to be in the
forecast, but with a transition to more western portions of the
forecast area by Wednesday as the upper ridge slides east.
Light winds and increased moisture will aide in the development of
fog for the next couple days. The main deciding factor on how dense
the fog becomes will be low level cloud development. Should see a
rapid improvement in visibilities as the surface heats up quickly.
LONG TERM...
Models are still showing the next significant weather impact to be a
cold front marching through the area Thursday afternoon and through
the overnight period. The initial wind shift looks to begin early
Thursday afternoon which is about 6 hours earlier than model runs
from 24 hrs ago. The GFS still shows more qpf than the ECMWF with
the frontal passage but has trended downward and closer to the more
typical events for this time of year. A significant drop in
temperatures is expected Friday through the weekend. 15-20 degree
drop in highs and lows are likely if model solutions don`t change
much between now and then.
Meffer
AVIATION...
Conditions are not expected to change much for this taf cycle. Fog
during the morning at most sites will dissipate by 9am and once
again tonight, fog should set back in for several terminals. TEMPO
groups should suffice for fog at the end of this 12z cycle. Low
ceilings will set in first and lower to the sfc late
tonight.
MARINE...
Models beginning to finally agree at least on timing of the cold
front moving through Thursnight. The 12z model run today should have
a better handle on temporal resolution and sensible weather. Will
keep forecast relatively similar to the current ongoing package.
Cold front slows as it approaches the coast but is not expected to
stall. Stronger forcing moves in behind the front causing it to move
rapidly through the coastal waters overnight and early Friday. Some
thunderstorm activity could accompany the front mainly over the open
gulf waters. Winds and seas will rise quickly behind the front and
could stay elevated into the weekend.
DECISION SUPPORT...
DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.
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 87 68 86 66 / 10 10 20 10
BTR 88 70 87 68 / 10 10 20 10
ASD 86 69 86 67 / 20 10 10 10
MSY 86 72 86 71 / 20 10 10 10
GPT 83 70 84 69 / 20 0 10 10
PQL 85 68 85 65 / 10 0 10 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
Area Forecast Discussion
National Weather Service Medford OR
548 AM PDT TUE OCT 18 2016
Updated Marine and Aviation sections:
.DISCUSSION...Near to the tail end of the recent snow event is
moving inland this morning with lightning accompanying the
heavier cells in the coastal water and on the coast. The HRRR is
handling this system well and is indicating yet another round that
will move through the cascades with snow ending a bit after
16-17Z. With this in mind have extended to advisory out past 17Z
to account for this and the morning commute traffic. The 500 MB
cold pool of -26C is roughly over the Cascades at 15Z with warmer
air moving in rapidly behind aloft as the system exits to the
east. Showers continue to taper off in onshore flow as the warmer
air aloft decreases lapse rates with an upper level ridge building
into the region. A warm front brushes the northern fringes of the
forecast area Wednesday, and with the upper ridge weakening
shifting east another cold front moves into the region Thursday
bringing another round of light to moderate rain, mostly from the
cascades westward in Oregon, as the front washes out over the
region. On the horizon the ECMWF is showing a moderate wind event,
with strong gales in the waters, moving in Monday. Sven
&&
.AVIATION...18/12Z TAF CYCLE...
Showers this morning will be locally intense, capable of dropping
visibilities to between 2 and 5 nautical miles in moderate rainfall
across the valleys. Outside of the showers expect a mix of MVFR and
VFR ceilings. There is a possibility of isolated thunderstorms along
and near the coast until 11 AM PDT. Snow levels will be in the 5kft
to 6kft foot range, with partial to near total terrain obscurations
this morning. Showers this afternoon will be mostly from Josephine
County westward, north of the Umpqua Divide, and from the Sprague
River Basin eastward. Expect VFR to prevail this afternoon for the
valleys, with partial mountain obscurations. Mid-level clouds are
expected to greatly limit low cloud and fog formation to the east
side and Northern California tonight into Wednesday morning. BTL
Note: The ceilometer at FAA site KOTH is out of service, so there
will be no ceiling observations available generally between the
hours of 04Z and 14Z.
&&
.MARINE...Updated 215 AM PDT Tuesday, October 18, 2016...
Steep west swell will continue to bring conditions hazardous to
small craft through early Wednesday morning. Meanwhile, the upper
level trough over the area will lift northeastward with the jet
stream this morning. West winds become southerly tonight through
Wednesday as the southern portion of a frontal system is expected to
stall over the area on Thursday before moving onto the coast
Thursday night. A stronger front is expected to arrive Sunday or
Monday. BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 10 AM PDT this morning for
ORZ027-028.
CA...None.
Pacific Coastal Waters...
- Small Craft Advisory for hazardous seas until 5 AM PDT Wednesday for
PZZ350-356-370-376.
$$
Area Forecast Discussion
National Weather Service Marquette MI
729 AM EDT Tue Oct 18 2016
.SHORT TERM...(Today and tonight)
Issued at 446 AM EDT TUE OCT 18 2016
00Z raobs/latest wv imagery and RAP analysis show the shrtwv
responsible for the heavy ra/svr storms yday evng exiting to the ne
along the most sgnft showers/TS. The associated cold fnt on the sw
flank of deepening lo pres moving into se Ontario has sank to the s
of all but the far scentral cwa. Despite some deep lyr qvector dvgc
in the wake of this disturbance, some showers/a few TS linger along
a line fm scentrl MN acrs nw WI into central Upr MI ahead of another
shrtwv aprchg fm the wsw and under axis of h85-7 fgen behind the
cold fnt and where mucapes up to 500j/kg and steeper mid lvl lapse
rates up to 7C/km linger per spc mesoanalysis/00Z MPX raob.
Farther to the nw, the 00Z INL raob shows a much drier sfc-h5 lyr,
but a good deal of hier clds linger in the mstr aoa h5 shown on that
raob and on the cyc side of the shrtwv supporting the lingering
showers.
Main fcst concerns in the short term wl be on pops today and then
cld/temp trends as the drier llvl air shown on the 00Z INL raob
grdly slides into the area.
Today...Incrsg deep lyr h85-3 qvector dvgc in the wake of stronger
shrtwv exiting to the ne with deeper convection is fcst to dominate
Upr MI, so expect the line of showers stretching fm scentral MN into
wcentrl Upr MI to diminish with time and probably by mid mrng as
they shift to the ese under axis of h85-7 fgen in the wake of the
departing sfc cold fnt. Plan to carry some sct showers thru mid mrng
mainly over the scentral. There wl be some gusty nw winds mainly
this mrng over the ne cwa in the wake of the departing/deepening sfc
lo pres, but these winds should diminish during the aftn as the pres
gradient weakens with the closer aprch of sfc hi pres toward the Upr
MS River Valley. The arrival of the drier llvl air depicted on the
00Z INL roab/larger scale subsidence/more acyc llvl flow should
result in clrg thru the day. Since h85 temps wl fall to only 6-8C by
00Z Wed, expect another relatively warm day with max temps in the
50s to as hi as the mid 60s over the se with the downslope NW flow.
Tngt...While there are hints some clds wl move into at least the wrn
cwa late as a weak shrtwv/lo pres trof aprch fm the w, lingering
llvl dry air/acyc flow most of the ngt wl maintain dry wx thru 12Z
Wed.
.LONG TERM...(Wednesday through Monday)
Issued at 443 AM EDT TUE OCT 18 2016
Nam shows a 500 mb shortwave over WY and another over the Canadian
prairies 12z Wed. Both of these shortwaves move east and help dig a
deep trough over the central U.S. on Thu and Thu night. Looks pretty
quiet for this forecast period, but could still see some lake effect
pcpn starting on Thu as colder air comes into the area and across
Lake Superior. 850 mb temperatures fall to -3C to -5C on Thu and
with lake temperatures from 9C to 12C, this is enough lake-850 mb
delta-t for lake effect pcpn. Did add in some pops for this with low
chance pops in northwest and north lake effect pxpn belts for thu
and thu night. Did not make too many changes to the going forecast.
In the extended, GFS and ECMWF show a 500 mb ridge over the desert
sw with a deep trough over the central U.S. 12z Fri. This trough is
very deep with the GFS and broader with the ECMWF with 850 mb
temperatures down to -4C to -7C 12z Fri and this cold air remains
over Lake Superior through 12z Sat. A shortwave moves through Sat
night into Sun morning. A broad 500 mb ridge moves into the Rockies
with a trough over the ern U.S. 12z Mon. Temperatures look to be
below normal for the start of this forecast and then get to near
normal by the end of the forecast period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 728 AM EDT TUE OCT 18 2016
As the wnw flow ahead of hi pres bldg toward the wrn Great Lks today
advects drier air shown on the 00Z INL raob into the Upr Lks, expect
lingering lo clds to clr out and give way to VFR conditions by early
aftn. There wl be some gusty winds much of the day at the more
exposed CMX location. These winds wl tend to diminish tngt with the
closer aprch of the sfc hi pres/loss of daytime heating.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 446 AM EDT TUE OCT 18 2016
Cancelled previous gale warning in effect for the e half of Lake
Superior as lo pres exiting to the ne is not intensifying as quickly
as anticipated, resulting in weaker nw winds up to only 30 kts in
this area. Then expect winds to diminish to under 25 kts by this
aftn and remain at 20-25 kts or less through the rest of the week as
a relatively weak pressure gradient dominates.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KC
LONG TERM...07
AVIATION...KC
MARINE...KC
Area Forecast Discussion
National Weather Service Albany NY
444 PM EDT Tue Oct 18 2016
.SYNOPSIS...
After a day of record-breaking warmth across the region, a cold
front approaching from the Great Lakes will cross the area tonight
into early Wednesday morning. Mainly isolated to scattered showers
will accompany the front. High pressure will build in on Wednesday,
with continued above normal temperatures. Low pressure is then
expected to develop and track northeastward from the Ohio Valley
region into the Northeast Thursday into Friday, bringing much needed
rainfall to much of the area.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 400 PM EDT...High temperature records have been broken at our
three climate sites this afternoon...Albany (83), Poughkeepsie (84)
and Glens Falls (83). Gusty south-southwest winds of 10-20+ mph and
abundant sunshine continuing late this afternoon across the region.
Clouds and some showers have developed around and just north of Lake
Ontario ahead of the cold front. Despite significant warming today,
instability profiles look rather meager, so generally expecting
showers with perhaps isolated thunder limited to the western
Adirondacks for a short time this evening. Coverage based on HRRR
and NSSL WRF output looks to be mainly isolated to scattered, with
the better coverage north and west of Albany. At least a few
separate rounds of showers may cross the western Adirondacks, so
have opted to mention likely pops there.
The showers and cold front should reach the Capital District around
or shortly after midnight, with coverage becoming more sparse
farther south and east with limited moisture. It will be a mild
night with temperatures only dropping into the 60-65 degree range
from around the Hudson Valley eastward, with slightly cooler mid to
upper 50s farther west behind the cold front.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
High pressure will build into the region on Wednesday, providing dry
conditions. After some early clouds, increasing sunshine is expected
through the rest of the day. Temperatures will be cooler than
Tuesday, but still well above normal for this time of year with no
significant change in air mass behind the "cold" front. Temperatures
should top out 10-15 degrees above normal with a light W-NW breeze.
Dry conditions will persist Wednesday night, as high pressure
gradually shifts eastward to Maine by sunrise Thursday. Temps will
be cooler than recent nights, although still close to 10 degrees
above normal with increasing clouds.
Conditions should become more unsettled on Thursday, as an inverted
trough associated with developing low pressure across the Ohio
Valley moves into western/central NY. The main focus for low level
convergence will be the surface trough, so based on its forecast
position, areas mainly north and west of east central NY will
experience steady/heavy rainfall. However, there should be enough
forcing for at least some measurable rainfall for much of the area.
Axis of steadier/heavier rain could set up across far NW portions of
Herkimer/Hamilton counties, but there are some differences in
forecast models regarding the exact position. It will be mostly
cloudy and cooler with the clouds and showers around.
A more widespread and steadier rainfall could move into more of the
region Thursday night into Friday, as the low pressure system is
forecast to track NE across Upstate NY. Again there are some slight
model differences in the track, which would have an impact on what
areas receive more rainfall. However, even if the low tracks
slightly farther north, the upper level trough is expected to deepen
upstream, with good moisture transport into our area courtesy of a
strengthening 850 mb southerly jet. GEFS indicating both PWAT and
wind anomalies approaching +2 to +3 std dev. by Friday, with the
potential for a narrow cold frontal rainband possibly providing a
period of downpours. We will have to see how this system evolves
over the next few days, but there at least the potential for some
decent rainfall.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The period will be marked by persistent troughing across the eastern
U.S. This means some precipitation likely and temperatures trending
cooler/colder.
An upper level low cuts off near the forecast area Friday night and
pulls north through the weekend. A surface low will be pulling north
into eastern Canada by Saturday.
Moist cool/cold cyclonic flow around the upper low and surface
system will yield likely POPS across the area on Friday night,
tapering to chance into the weekend. There is the chance for some
snow or rain snow mix across the higher elevations of the
Adirondacks Saturday night through Sunday night. Not expecting any
significant accumulation.
Some differences in the models appear Sunday night with the ECMWF
scooting a clipper system across PA and NYC. While the CWA would be
on the north side of this system, 925mb temps look too warm for any
snow. The current forecast, from the SuperBlend, does not account
for this system keeping POPS dry on Sunday night.
While there are timing differences between the GFS and ECMWF on when
the core of the coldest air resides over the CWA, it is clear that
temperatures through the period will average 5-10 degrees below
normal. Look for high temperatures to struggle to get out of the 30s
across the Adirondacks Saturday-Tuesday.
The latest forecast from the National Hurricane Center on the system
east of the Bahamas calls for an 80 percent chance of development
over the next 5 days. The NHC forecast has the system heading
northeastward out to sea by the end of the week.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
A cold front will slowly approach from the west tonight with
isolated to scattered showers especially north and west of the
Interstate 90 corridor. The front will move south of the region by
tomorrow afternoon with high pressure building in.
VFR conditions are expected prior to 04Z/WED. Mid and high clouds
will increase towards 00Z especially north and west of KALB. The
clouds will continue to thicken and lower shortly before or just
after midnight with bases in the 4-6 KFT AGL range. The best
chance of showers will be from KALB-KPSF north and west. VCSH
groups were used at 03Z-05Z with a brief period of showers between
06Z-11Z at KGFL/KALB. The skies may clear between 09Z-12Z with
residual moisture in the boundary layer before the wind shifts and
the cold advection kicks in especially for KGFL/KPSF so a brief
window of IFR mist is included...as well as MVFR conditions. Our
confidence is not high at KALB/KPOU and brief MVFR conditions in
terms of CIGS/VSBYS were used.
VFR conditions should return quickly between 12Z-15Z/WED with
clearing skies and strong subsidence with the frontal passage.
The winds will be southerly at 8-15 kts with gusts close to 20-25
kts at KALB/KPSF prior to 00Z/WED. The winds will continue from
the south to southwest ahead of the front at 5-10 kts
tonight...but may decouple at KGFL/KPSF/KPOU to 5 kts or less. The
winds will increase in the wake of the front from the west at 5-10
kts after 12Z/WED.
Outlook...
Wednesday Night: Low Operational Impact. NO SIG WX.
Thursday: High Operational Impact. Likely SHRA...RA.
Thursday Night: High Operational Impact. Likely RA.
Friday: High Operational Impact. Likely RA.
Friday Night: Moderate Operational Impact. Likely SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.
Saturday Night: Low Operational Impact. Slight Chance of SHRA.
Sunday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
After a day of record-breaking warmth across the region, a cold
front approaching from the Great Lakes will cross the area tonight
into early Wednesday morning. Mainly isolated to scattered showers
will accompany the front. High pressure will build in on Wednesday,
with continued above normal temperatures. Low pressure is then
expected to develop and track northeastward from the Ohio Valley
region into the Northeast Thursday into Friday, bringing much
needed rainfall to much of the area.
Relative humidity values will increase to around 90 to 100 percent
tonight, then drop to minimum values of between 45 and 60 percent
Wednesday afternoon. RH values will increase to around 90 to 100
percent Wednesday night.
Winds tonight will be south-southwest around 10 to 20 mph with some
higher gusts this evening. Winds will shift to the west-northwest on
Wednesday around 5 to 10 mph. Winds will be light and variable
Wednesday night.
&&
.HYDROLOGY...
A cold front move southeast across the region tonight into early
Wednesday, bringing mainly isolated to scattered showers. Overall,
rainfall amounts through will be light, generally less than one
tenth of an inch, but up to two tenths of an inch across portions of
the western Adirondacks.
Dry weather expected Wednesday into early Thursday morning, before a
developing low pressure system tracks northeast from the Ohio Valley
region, which should bring much needed soaking rainfall to at least
parts of the region Thursday through Friday. Best chance for
appreciable rainfall looks to be for areas north and west of the
Capital District.
The latest US Drought Monitor continues to show drought conditions
have worsen across portion of the area. Precipitation departures
this calendar year are 5 to 15 inches below normal, with the
greatest departures across southeastern parts of the HSA.
As a result, streamflow and ground water levels have been running
well below normal.
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.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...JPV
NEAR TERM...JPV
SHORT TERM...JPV
LONG TERM...OKeefe
AVIATION...Wasula
FIRE WEATHER...JPV
HYDROLOGY...11/JPV
Area Forecast Discussion
National Weather Service Columbia SC
634 PM EDT Tue Oct 18 2016
.SYNOPSIS...
An upper-level ridge across the area will weaken allowing an upper
level trough to cross the region Friday through Saturday. Surface
high pressure will be in control of the region through Wednesday
night. A cold front with will move across the area Thursday night
and Friday morning. Cooler and drier air will move in behind the
front for the weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Surface and upper level ridging will continue over the region
tonight. Atmospheric moisture is limited and shallow, favoring the
eastern Midlands. Patchy fog may develop with strong radiational
cooling overnight but a 15 to 20 knot low level jet may keep the
boundary layer mixed at times. HRRR indicating some possible
stratus clouds may develop across the far eastern Midlands but
confidence is low. Lows will be in the upper 50s to lower 60s.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
Dry weather along with well above normal temperatures are forecast
to continue Wednesday and Thursday. An upper-level ridge
entrenched over the Deep South and Southeastern states will begin
to weaken Thursday as a deep trough digs into the Mississippi
Valley. Surface high pressure will also weaken Thursday as a cold
front approaches from the west. With strong insolation and
subsidence...model consensus indicated maximum temperatures above
normal in the mid to upper 80s. Despite strong radiational cooling
at night overnight temperatures above normal in the mid 50s to
lower 60s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Models are in good agreement with approaching upper level trough
crossing the region Thursday night into Friday night. This
progressive trough is forecast to amplify and become negatively
tilted Friday. Models are consistent with subtropical low moving
well offshore to the northeast as the upper trough approaches. A
cold front should move through the region early Friday with cold
advection developing during the day. Moisture appears limited
along the front and mos pop consensus continues to decrease. Have
indicated only a slight chance for showers late Thursday night
into Friday associated with frontal passage and upper trough. The
front may come through dry. Saturday appears dry across the region
with downslope flow. Dry and much cooler...more seasonable weather
is forecast behind the front through early next week as surface
high pressure returns to the region.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
Mostly clear skies and SW winds less than 7 knots through the
rest of the day. Light and variable winds return around sunset.
A 15 to 20 kt LLJ, similar to the previous night, will help keep
lower levels marginally mixed. Moisture looks more shallow tonight
so may see OGB only lower to MVFR, possibly IFR, conditions
rather then the periods of LIFR vis/cigs seen this morning. AGS
will likely see IFR/LIFR conditions given similar conditions to
the previous night and a nearby moisture source. All other sites
are expected to remain VFR during the period.
Wednesday, another dry, warm day expected with mostly clear
skies. Winds will be light and mainly out of the SW but may become
variable at times.
EXTENDED AVIATION OUTLOOK...MVFR or IFR stratus and fog possible
each morning through Thursday. Restrictions possible in scattered
showers Friday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
NEAR TERM...HC
Area Forecast Discussion
National Weather Service Grand Forks ND
248 PM CDT Tue Oct 18 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 248 PM CDT Tue Oct 18 2016
How to handle spotty showers tonight will be the main issue for
the period.
Upper flow is nearly zonal, with several weak shortwaves moving
through. One shortwave was seen on water vapor loop right along
the ND/SD/MN border area, while there is another one evident
further west in central ND. Light showers have continued to
develop and then fizzle out as they move east today, but there is
now an upward trend in Barnes/Cass counties. The RAP and HRRR
develop more shower activity further to the north in the next few
hours as the shortwave over central ND approaches. Will expand the
POPs mention for this evening, but most of the showers should be
done before midnight as the shortwave exits off to the east.
Tomorrow will be quiet with a weak surface high over the region.
As for temperatures, a surge of cold air will begin to move in
from the north overnight, with 925mb temps dropping back below
zero. The northwestern counties will see the brunt of the cold air
advection but also will have some clouds for much of night, so
kept lows near the 30 mark. The southern counties should be a bit
higher in the upper 30s with less clouds but with some mixing
winds and a warmer start. The cool air mass will continue through
Wednesday with highs ranging from the low 40s north to low 50s
south.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 248 PM CDT Tue Oct 18 2016
Thursday through Friday...This time frame should be mainly dry
with a cool Thu followed by a milder Fri as mid level ridging
builds this way. A low POP for some mixed pcpn is included
vicinity of LOW for Thu morning as trough axis swings through that
area near time of min temps. Both the GFS and ECMWF agree on
timing and placement of this feature. The next hint of any more
precip would occur by Fri afternoon owing to weak WAA over mainly
northwest CWA.
Saturday through Tuesday...Still not a whole lot of activity as we
head through the weekend and into early next week. ECMWF brings a
reasonably robust short wave over northern forecast area later
Saturday into early Sunday; GFS solution is more of a slight
flattening of the ridge with much less QPF. Above freezing min
temps and a mild Sunday would make this an all liquid affair. The
ridging still seems to want to hang around into early next week
keeping temps on the mild side of normal, with a more
southwesterly flow leading to a possible showery period at the end
of our time frame.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1234 PM CDT Tue Oct 18 2016
MVFR conditions continue at KDVL, KTVF, and KBJI sites, although
there should be some improvement to VFR later this afternoon. Much
of the mid cloud has been to the north, but there has been some
patchy stratus and mid cloud across the central and southern
forecast area also. Think that the stratus tonight will stay
mostly to the north of the TAF sites, but may have to re-evaluate
as the night goes on. Some scattered light rain showers are
possible but they will be isolated enough to not include in the
TAFs. Winds will remain from the northwest.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
SHORT TERM...JR
LONG TERM...WJB
AVIATION...JR
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
219 PM CDT Tue Oct 18 2016
.SHORT TERM...
140 PM CDT
Through Wednesday...
A cold front continues to push across the region this afternoon,
and stretches from roughly Gary through Pontiac at 18Z. Out
ahead of the front, temperatures in the upper 70s with dewpoints
in the mid 60s will contribute to close to 1000 J/kg MLCAPE by mid
afternoon, so cannot rule out a shower or isolated thunderstorm
developing but better chances will be off to our east where there
is very modest upper support associated a sheared shortwave
pushing across the Great Lakes. Behind the front, winds are
turning northwest and easing while skies are clearing out. Latest
runs of the RAP and HRRR continue to suggest a lake breeze will
form and push inland across NW Indiana and a little into Cook
County mid to late this afternoon which will hasten temperatures
dropping back through the 60s for those areas. Otherwise, expect
quiet weather this evening and overnight as high pressure builds
towards the mid/upper Mississippi Valley.
High pressure will continue to dominate most of the day Wednesday
providing light northeast flow and primarily dry conditions.
Despite the cold frontal passage, we will continue to experience
above normal temperatures Wednesday with mid to upper 60s north of
I-80 and low 70s along and south of I-80. An upper level
disturbance currently digging across the Inter-mountain West is
progged to lift across the central plains Wednesday. Weak mid
level height falls will begin to overspread the local area by mid
to late in the afternoon with increasing mid and high clouds.
Models do generate some QPF up through roughly the I-80 corridor
by 00Z tomorrow evening, though soundings show dry air persisting
below 700mb. Could be some high-based light showers or sprinkles
moving up from the south into the local CWA, but better chances
for showers will be closer to the baroclinic zone stretching from
downstate Illinois into southern/central Indiana.
Deubelbeiss
&&
.LONG TERM...
210 PM CDT
Wednesday night through Monday...
A transition back to more seasonal weather is on tap for the extended
period.
NAM/GFS both depict fairly strong frontogenesis with the cold
front Wednesday night in the clash between our anomalously warm
airmass of late and the colder continental air arriving from the northwest.
This will be coupled with strengthening low pressure from the
left rear quadrant of an upper level jet stream and should result
in an increasing precipitation shield across the region Wednesday
night. At this point the better co-location of forcing and
moisture will remain draped south and east of our area, but there
should be enough for some bands of lighter to even moderate rain
across the I-55 corridor southeastward and possibly even extending
farther into northeast IL. This forcing continues through the day
Thursday with the jet in the region, an approaching pacific
shortwave trough axis and a strengthening surface low continuing
the deformation precipitation across much of Indiana with some
lower chances across Northwest Indiana. Expect more clouds than
sun.
While colder air slowly bleeds in during the day Thursday, a secondary
surge of colder air will be shoved southeastward by a portion of
the Canadian upper trough will reinforce the changing airmass.
Models depict this will be a largely dry frontal passage, but do
portray some lake effect rain showers across northwest Indiana.
The convergence signal is somewhat weak and progressive and
moisture is but the thermodynamic signal is robust to suggest
there will be some lake effect showers with fairly high
confidence, but lowered confidence on how widespread and how long
lasting. Areas away from the lake will have sunshine but cool
conditions and area wide highs in the 50s, some low 50s north.
High pressure returns Friday night and Saturday which look dry,
in spite of the EC painting some light precip along an elevated
warm frontal boundary as the high approaches. An upper wave will
pass by to our north on Sunday which will initially lead to
slightly warmer conditions, though there are better indications of
a backdoor cold front sometime later Sunday into Monday. The front
holds off till after sunset on the GFS, midday/afternoon on the
EC/GFS. This will setup a frontal zone across the local area which
may serve as a focus for increased precipitation chances Tuesday
or into the middle of next week.
KMD
&&
.AVIATION...
For the 18Z TAFs...
A cold front is pushing across the region this afternoon with
winds turning NW and becoming less breezy behind. MVFR cigs have
mostly dropped southeast of the terminals this afternoon and
expect VFR to prevail through the remainder of the period. As
winds continue to diminish this evening, a lake breeze is expected
to form and push inland across GYY and likely MDW where winds will
shift to NNE or NE respectively. Winds will become light and
variable after sunset and overnight, then expect a light N or NE
wind during the day Wednesday.
BMD
&&
.MARINE...
210 PM CDT
Today`s cold front has cleared the lake as low pressure across
northern Quebec exits the region. High pressure across the
Canadian Rockies will creep southeastward into the upper Midwest
and plains region over the next few days. Meanwhile, and area of
low pressure currently stretched across the Ohio valley and into
the southern Plains will lift northeast toward the latter half of
the week. In between these two systems a cold front will pass
south across the lake Wednesday night with a tightening pressure
gradient resulting in gusty north winds Thursday. With the
persistent north winds behind the front, expect waves to build on
the south end of Lake Michigan and result in dangerous conditions
for small craft Thursday into Friday. The high will weaken some
Friday as the low continues to strengthen across the northeastern
United States Friday. The high pressure ridge will move east of
Lake Michigan Sunday and will result in a shift to southerly winds
briefly before a backdoor cold front results in a shift back to
northeast winds.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Mobile AL
352 PM CDT Tue Oct 18 2016
.NEAR TERM /Now Through Wednesday/...An upper level ridge of high
pressure remains the dominant feature across much of the Gulf Coast
region this afternoon, while a surface ridge of high pressure
continues to extend from the Western Atlantic through the
Southeastern U.S. Large scale subsidence and deep layer dry air is
generally keeping the region rain-free this afternoon, with the
exception of a couple of very isolated small and brief showers near
the immediate coast. Visible satellite imagery otherwise shows a
decent cumulus field across the region this afternoon and surface
observations continue to indicate above normal temperatures with
readings in the mid 80s near the coast and in the upper 80s to around
90 inland.
The upper level ridge of high pressure will continue to build
eastward over the Central Gulf Coast region tonight and eventually
over the Southeastern U.S. Wednesday. Though a very isolated shower
cannot be entirely ruled out mainly over far western portions of the
forecast area late tonight and Wednesday, deep layer subsidence and
low precipitable water values will preclude mentionable rain chances
in the forecast through Wednesday. Forecast soundings indicate a very
shallow moist airmass in place across much of our area tonight, which
will be a favorable setup for fog formation late. High resolution
and probabilistic data, including the HRRR, RAP and SREF all
indicate the potential for patchy to areas of fog to develop late
tonight and early Wednesday morning, particularly over interior
portions of the region. Fog could at least become locally dense, and
later shifts will need to monitor trends for a potential Dense Fog
Advisory. We added fog mention to the weather grids for a few hours
late tonight into early Wednesday morning. Otherwise, an unseasonably
warm and humid airmass will remain in place across our region through
Wednesday. Lows tonight are forecast to range from the lower to mid
60s inland, and in the upper 60s to around 70 near the immediate
coast and beaches. Highs Wednesday will once again range from the mid
80s near the beaches to the upper 80s to around 90 inland. /21
.SHORT TERM /Wednesday night Through Friday night/...Wednesday
through Thursday night, shortwave energy just east of the US Rockies
digs south over the Plains, then swings east, pushing a weakening
front across the fa Thursday night. At this point, guidance is
advertising the wind shift portion of the front staring across the
fa around 00z Fri and just southeast of the marine portion of the fa
by around 09z. Any chance for severe weather will be very low, with
instability being lost as the fa heads into the night time hours.
Enough instability may be present in the early to mid afternoon
(1000-1500j/kg) for a strong to severe storm, mainly along and west
of the Alabama/Mississippi state line with a bit better low level
southerly flow. Wind shear will be generally on the weak side,
though, with 0-3km helicities at 20 m^2/s^2 or less during the late
afternoon close to the front. Also, any decent upper support remains
well north of the fa, over central and northern Alabama. All in all,
am not going to raise the severe weather with this fropa, just a
keep an eye on the weather over Mississippi.
For the numbers for Wednesday through Thursday night, with the
continued southerly flow and an upper high slowly slowly shifting
east over the Southeast, temps well above seasonal, ranging from mid
60s inland to around 70 along the coast. Do not see shra lasting
much into the evening hours, if at all. With moisture levels on the
high side, overnight fog development is again likely, with a few
localities dipping into the dense category closer to sunrise. Temps
Friday remain well above seasonal levels as the upper high brings
enough subsidence when combined with the southerly flow to being
temps well above seasonal. Highs in the low to mid 80s expected with
a chance of shra/tsra. Thursday night, as the front crosses the fa,
temps drop closer to seasonal levels as the front and its rain moves
southeast of the fa and skies clear.
Friday through Friday night, cooler air overspreads the fa, bringing
temps around to a bit below seasonal to the area. /16
.LONG TERM /Saturday Through Tuesday/...As the Thursday/Thursday
night weather making upper trough moves off the Eastern Seaboard
through the weekend, An upper ridge builds east over the Gulf of
Mexico and associated coastal areas. A ridge shifts east over the
Plains, pushing a surface high that settles over the Southeast
behind the front eastward a bit, but the moisture returning onshore
flow remains well west of the fa. Subsidence from the upper level
high pressure building/shifting over the fa will bring temps rising
back to well above seasonal levels, mainly during the day, but with
a dry airmass remaining over the fa, overnight lows around to a bit
below seasonal remain. /16
&&
.MARINE...Surface high pressure will continue to ridge across the
Western Atlantic and Southeast States through Wednesday night, before
weakening Thursday in advance of an approaching cold front. The front
is forecast to push across the marine area late Thursday evening into
Thursday night, and will be followed by building high pressure into
the Northern Gulf and Southeast States through the weekend. A
generally light to occasionally moderate southerly to southeasterly
flow this evening will gradually become southeasterly to easterly by
Wednesday. A moderate to strong offshore flow will spread across the
marine area Thursday night into Friday following frontal passage.
Wind speeds may reach advisory criteria Thursday night, potentially
lasting into Friday night over the offshore waters, and possibly some
of the bays and sounds. Winds should veer northeasterly to easterly
and slacken late Saturday night into Sunday as high pressure shifts
east and the gradient weakens. /21
&&
.PRELIMINARY POINT TEMPS/POPS...
Mobile 67 87 65 86 / 10 10 10 10
Pensacola 69 86 67 86 / 0 0 10 0
Destin 70 85 70 82 / 0 0 10 0
Evergreen 63 90 61 87 / 0 0 10 10
Waynesboro 65 89 65 86 / 10 10 10 30
Camden 64 89 62 88 / 10 0 10 10
Crestview 61 90 59 87 / 0 0 10 0
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
342 PM CDT TUE OCT 18 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 341 PM CDT Tue Oct 18 2016
Most exciting thing happening during the short term is a weak cold
front currently up across central NODAK into northern MN will work
across the area tonight, exiting off to our southeast Wednesday
morning. Atmosphere is pretty dry in the wake of Mondays front
(which is now stretching from around St. Louis up into western
Quebec), so rainfall and even cloud cover will be lacking with this
front. However, a pocket of weak instability has developed ahead of
the front over central ND, with a few showers noted on regional
radar between Bismark and Fargo. RAP MUCAPE forecast shows this
pocket of instability weakening considerably as it works toward MN,
which means those showers in ND will be quickly running out of steam
as they cross into MN. As a result, have kept the forecast dry,
though a stray sprinkle or two can not be ruled out up by Alexandria
between 6pm and 10pm.
The passage of the cold front tonight will continue to chip away at
temperatures/dewpoints, with h85 temps dropping from around +6C
today to around +2C tomorrow. This will result in highs about 5
degrees colder than what we are seeing this afternoon. Did not stray
to far from SuperBlend temperatures tonight, with highs tomorrow
lowered slightly from SuperBlend values, closer to what you get when
mixing down from 900mb.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 341 PM CDT Tue Oct 18 2016
The Wednesday night through Tuesday forecast remains on track. Dry
weather is expected for nearly the entire period. Temperatures on
Thursday will be in the mid 40s to near 50, which is around 5
degrees below the seasonal average for mid-October. Temperatures on
Friday will rebound slightly, with above normal temperatures
expected Saturday through Tuesday.
Precipitation chances are near zero the entire period. A weak wave
will bring showers over the Missouri River Valley Wednesday night,
but these should stay south and west of the forecast period so
removed pops during this time frame. On Friday warm air advection
will bring a band of light rain across northern MN, but not
anticipating much if any rainfall in the Twin Cities forecast area.
Continued with a 15 to 20 percent chance, but nothing more. Finally,
the 18.12Z ECMWF has changed considerably from its 00Z counterpart.
It is much more amplified and slower with the precip at the end of
the period keeping Tuesday dry. The GFS is trending this way as
well. For now have a 30 to 50 percent chance of rain.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1229 PM CDT Tue Oct 18 2016
A VFR period is forthcoming with only issue with the TAFs is the
timing of a cold front across the area tonight. This front is
currently up in northern MN and will slip through AXN first around
6z and EAU last shortly after 12z. This is what results in the wind
trends seen in the TAFs from west today, to WSW this evening, and
back to the NW for tomorrow. Lack of moisture behind the front that
clear through here last night will keep the front both dry and
clouds above 10k ft.
KMSP...frontal timing for MSP looks to be between 10z and 14z. Winds
will remain on the light side though and generally stay below 8kts.
/OUTLOOK FOR KMSP/
Thu...VFR. Wind NW 5-10 kts.
Fri...VFR. Wind SE 5 kts.
Sat...VFR. Wind S 5 kts.
&&
.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...JRB
AVIATION...MPG
Area Forecast Discussion
National Weather Service Marquette MI
349 PM EDT Tue Oct 18 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 349 PM EDT TUE OCT 18 2016
Water vapor imagery and RAP analysis show wsw flow extending from
the Great Basin to western Quebec. Pair of strong shortwaves that
brought the shra/tsra and heavy rainfall to parts of Upper Michigan
last night are over Quebec, powered ene by 120kt upper jet. Shallow
moisture behind these systems and the low sun angle at this time of
year allowed low clouds to persist over much of the area this
morning. Even this aftn, it`s been a slow process clearing the
clouds with only the sw portion of the area now seeing mostly sunny
skies. A few -shra have even developed recently in Delta and sw
Schoolcraft counties where some sunshine has resulted in a little
instability.
During the short term, broad shortwave trof moving across the
western CONUS will begin to sharpen up as it moves out over the
western Plains on Wed. Meanwhile, a separate trof over Manitoba will
shift over northern Ontario on Wed as well. As these changes occur
at the mid levels, very gradual caa will drop 850mb temps that are
currently 6-7C down to around 0C over the Keweenaw to 4C over the se
fcst area by 00z Thu. With western Lake Superior water temps roughly
down to around 10c, lake effect pcpn won`t be a concern during the
short term. Couple of weak shortwaves and an associated sfc trof may
generate a few -shra or sprinkles. Given the overall weak forcing
and lack of deep moisture will leave pcpn out of the fcst. However,
there are some -shra in ND this aftn, so it`s certainly not out of
the question that there could be some -shra/sprinkles late tonight
and Wed. Temps on Wed will still be above normal over the e half of
the fcst area with highs in the upper 50s/lwr 60s. Over the far w,
highs will be around 50F into the lwr 50s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 343 PM EDT TUE OCT 18 2016
Upper trough is forecast to deepen late this week from the middle
conus to the Great Lakes. Conditions will turn cooler across Upper
Michigan with daytime temperatures falling a little below normal in
the 40s Thu-Sat. Normal highs are upper 40s to lower 50s. Temps at
about 5kft or h85 should be around -4c to -6c. Those h85 temps with
Lk Superior water temps 8-13c will result in delta t/s 12-19c which
is sufficient for some lake effect precipitation. Best chance for
precip will be Thu night into Fri morning as deeper moisture arrives
and inversions rise up to 7-8kft. Additional support for precip will
be from at least weaker shortwave energy moving through and uptick
in low-level convergence as sfc trough works across Lk Superior and
northern Upper Michigan. Low-level flow looks more cyclonic than it
did 24 hr ago, so overall the setup will be favorable for light to
perhaps moderate lake effect. Location of strongest, persistent
convergence is subject to change but attm looks like would affect
north central Upper Michigan on Fri morning. Ptype in this area
should remain rain with close proximity to warmer Lk Superior waters
and as 1000-850mb thickness remain above 1300m and sfc temps stay
aoa 38-39F. Farther inland west, wbzero heights blo 1000agl and sfc
temps aob 35F would support some snow mixing in with the rain, but
attm the overall coverage and intensity of precip for these areas
looks minimal.
Mean trough then deepens further over Quebec and the northeast conus
through the weekend while nw flow aloft continues across the Great
Lakes. Still uncertainty on how weekend works out. Even though axis
of mean trough will be well to the east and heights will try to rise
some, there may be additional shortwaves digging across area serving
to keep at least weak troughing in place. Any upper level system
working through will be moisture starved though as deep moisture
will be wrapped up in strong low spinning over Quebec. Just slight
chance pops for the weekend into early next week with temps around
normal.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 144 PM EDT TUE OCT 18 2016
Drier air has been slower to reach KCMX than expected today. Back
edge of lower clouds is currently near the western shoreline of the
Keweenaw, but is being held up by the upslope westerly flow. Should
see low MVFR conditions break out to VFR there around 20z. May see a
period of MVFR cigs at KSAW over the next hr or two before shallow
moisture is pushed/mixed out. Other than these initial lower
conditions, drier air mass settling into the area will lead to VFR
conditions being the rule at KIWD/KCMX/KSAW.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 343 PM EDT TUE OCT 18 2016
Expect winds to remain 20-25 kts or less through the rest of the
week and into the weekend as a relatively weak pressure gradient
dominates.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...JLA
AVIATION...Rolfson
MARINE...JLA