Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/01/16
Area Forecast Discussion
National Weather Service Denver/Boulder CO
849 PM MDT Fri Sep 30 2016
.UPDATE...
Issued at 841 PM MDT Fri Sep 30 2016
Showers will come to an end over the next few hours in
Park...Elbert and Douglas counties with mostly cloudy skies over
the mountains moving to partly cloudy on the plains. Temperatures
will be cooler then last night due to less nocturnal cloud cover.
Made adjustments to pops and weather to be more
representative...otherwise forecast is on track.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 645 PM MDT Fri Sep 30 2016
Today and tomorrow a weak upper trough will be slowly moving east
through the weak upper ridge over Colorado. The airmass over
Colorado is quite moist (GJT was over 200 percent of average this
morning) and there were numerous cloud levels over the mountains.
There is some clearing seen in the higher clouds over Colorado...
and we just now seeing lightning over the western mountains. At
the surface a low pressure center resides over southeast
Colorado...and an apparent front went through metro Denver this
morning and is seen moving through the Pueblo radar at 20z. The
boundary and the clouds resulted in slightly cooler temperatures
today.
New HRRR continues the idea of precipitation shifting to the
southeast this evening. That is reflected in the forecast so no
changes...scattered pops over the Palmer Divide this evening...then
showers diminishing across the CWA by midnight.
Saturday will be similar...as the moisture will continue to reside
over the mountains and the southwest flow will continue. There will
be scattered showers and thunderstorms over mountains...with a much
lower chance over the plains. Temperatures will be only a degree or
two higher than today.
.LONG TERM...(Saturday night through Friday)
Issued at 645 PM MDT Fri Sep 30 2016
Saturday night the upper level trough will be centered over the
Rocky Mountain Region...with a deep upper level low pressure
trough just off the west coast of the United States. On
Sunday...the upper ridge will shift eastward over the Central
Plains as the upper level storm system deepens over northern
California. This pattern should result in dry and warm weather
across north central and northeastern Colorado through the
weekend...with only isolated showers and storms in the mountains.
On Monday...the upper trough deepens over the Great Basin...with a
moderate to strong southwesterly flow aloft over Colorado. Models
are showing a 100kt+ KT jet over western Colorado by Monday
Afternoon. Some orographic and lift from the upper jet should
produce scattered afternoon and evening showers and storms over
the high country...with dry and warm weather east of the
mountains.
On Tuesday...the center of the upper low tracks north of Colorado.
The GFS has it moving over Wyoming and the Dakotas...while the ECMWF
moves it over Montana. The combination of the frontal passage and
cold air advection from the upper trough will bring an end to the
unseasonably warm temperature across the region. Temperatures on
Tuesday should be 15 to 20 degrees colder than Monday`s readings.
Cold advection behind the front...combined with the gradient between
the upper high over the northern Rockies and higher pressure over
Colorado should produce gusty winds over the foothills and portions
of northeastern Colorado from early Tuesday morning through Tuesday
afternoon. The Sangster Model suggests the potential for strong
winds across the foothills. In addition...the northern mountains
should see a good chance for snow due to cold air advection and
orographic westerly flow.
Wednesday should be the coolest day of the week on the plains due to
increasing cloudiness and less downslope flow. We should still see
scattered snow showers in the mountains due to a continued westerly
orographic flow. The models also show an upper level disturbance
moving across the region...which could produce isolated showers
across the plains.
Warmer and drier weather is expected by Friday as upper level high
pressure rebuilds over the Rocky Mountain Region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 841 PM MDT Fri Sep 30 2016
VFR conditions are expected for the next 24 hours. Winds will
move to drainage by 3z and stay from the SW through the period
with light speeds. Ceilings will remain until around 4z with a SCT
deck through tomorrow afternoon until another round of moisture
will bring an upper level BKN deck with thunderstorms possible in
the vicinity. I am not confident that DIA will see convection on
station but there is still a 10-20% chance of some development by
the late afternoon.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Bowen
SHORT TERM...RTG
LONG TERM...Kalina
AVIATION...Bowen
Area Forecast Discussion
National Weather Service Cleveland OH
959 PM EDT FRI SEP 30 2016
.SYNOPSIS...
Low pressure over western Kentucky will slowly lift north into lower
Michigan by Sunday then shift east of the forecast area Monday.
Large area of high pressure will move across the Great Lakes Monday
and move off the New England Coast late Tuesday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Latest HRRR model trying to match itself with reality with patches
of rain occurring through the night. Some locations may get hit
with a stray shower passing through while others like northwest
Pennsylvania and extreme northeast Ohio will get caught under the
large batch of showers moving north across western Pennsylvania
late in the overnight hours. Another area will move northwest into
the western portions of the area. So, this makes pinpointing the
forecast rather difficult so I tried to highlight the best
locations where rain will occur overnight. Will keep mention of
isolated thunderstorms because just about any where in the area
could see a stray cell or two produce some thunder. Otherwise,
temperatures are not going too far with all of the clouds and
showers around at this time.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
Models coming into a little better agreement on the track and timing
of the low. But again...today the models are a little slower
ejecting the low than they were yesterday. The upper level low
drifts north into Lower Michigan by Saturday evening. Both the
upper level and surface low linger over the Central Lakes Sunday.
Best focus will be over the Central Lakes into the primary snowbelt
area. High pressure finally starts to eject the low on Monday. Left
chance pops going in the east because models still may be a tad fast
with the low...and potential for some lake enhanced showers off the
lake with 850mb temps around 8c. Very little change in the temps
through Monday.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The models are in reasonably good agreement with the upper low
finally sliding off the east coast later Monday/Monday night.
There is still a hint of low pressure aloft left behind as the rex
block forms over the Great Lakes but let us assume that there will be
enough high pressure and subsidence given the time of year that dry
weather will prevail through mid week.
Not very confident about the timing of next cold front. It will
likely have to wait for the tropical system going up the east coast
unless a weakening front sneaks through quick enough as suggested
by the ECMWF. Will mention a small chance of showers Thursday for
northwest Ohio and keep a small chance of showers Friday given the
uncertainty.
Temperatures should rebound nicely as the ridge builds aloft with
highs in the 70s. It will get cooler later in the week but not very
confident on the forecast temps until we figure out the timing of the
next front and the amount of clouds and showers.
&&
.AVIATION /00Z Saturday THROUGH Wednesday/...
Upper level low pressure system will continue to spin over the area
with occasional showers. Showers have been decreasing in coverage
but will continue at times through Saturday. Isolated
thunderstorms will also be possible but not enough coverage to
include in any of the TAFs. MVFR ceilings are filling in with
periods of IFR developing overnight, especially in the 06-13Z.
The low will gradually start to shift north on Saturday with
easterly winds shifting around to the south. Ceilings will improve
through the day Saturday and be VFR most areas by 17Z.
OUTLOOK...Non-VFR in showers and low ceilings at times into
Monday.
&&
.MARINE...
The east winds will gradually relax and as the persistent low
pressure area over the Ohio Valley weakens and drifts back toward the
Great Lakes this weekend but the wind and waves will remain high
enough to keep the small craft advisory posted into tonight. The flow
will veer more from the south over the weekend and then veer
northwest on Monday as the low moves east.
High pressure will build in Monday and Tuesday. The center of the
surface high over eastern Canada will result in winds veering all the
way northeast late Tuesday into Wednesday so the west half of the
lake could get a bit choppy.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EDT Saturday for LEZ142>147.
&&
$$
SYNOPSIS...DJB
NEAR TERM...Lombardy
SHORT TERM...DJB
LONG TERM...Kosarik
AVIATION...KEC
MARINE...Kosarik
Area Forecast Discussion
National Weather Service Duluth MN
645 PM CDT FRI SEP 30 2016
.SHORT TERM...(This evening through Saturday)
Issued at 306 PM CDT Fri Sep 30 2016
Summary: Persistent easterly flow from Lake Superior will
maintain a similar weather pattern into Saturday. Marine stratus
will surge back inland this evening and overnight, only to linger
again Saturday morning before dissipating for inland areas
Saturday afternoon, but remaining over the Lake. Low temperatures
will again fall into the 40s tonight, and lower to middle 60s are
expected Saturday afternoon.
A large, vertically-stacked area of low pressure over Kentucky
will wobble its way north to Indiana/Ohio by Saturday, while a
ridge of surface high pressure will continue to extend from Quebec
through northern Ontario into Minnesota. This pattern will
maintain light easterly flow across the Northland, which will be
relatively humid because of the moisture contribution from Lake
Superior.
The Northland saw stratus from Lake Superior spread to most of
the Northland last night and early this morning, only to linger
well into the day. The Lake is fairly warm, with a surface
temperature in the low 50s, while temperatures inland fell into
the 40s last night. The relatively warm and humid air from the
lake easily clouded over as it ran over the cool air inland. The
stratus gradually dissipated through today to result in most areas
clearing, but it remained over Lake Superior and slightly inland
downwind of the Lake, such as near the shores of the Twin Ports
and Ashland. The overall weather pattern will not be changing to
any significant degree into tomorrow, so it looks like the
Northland is stuck in repeat mode. The HRRR has been handling the
stratus the best amongst the models, and it has the marine stratus
surging back inland this evening and overnight. Increased the
cloud cover forecast for tonight and tomorrow with a heavy
influence from the latest HRRR runs. Other models support/suggest
the marine stratus moving back inland tonight for most areas, too,
such as the 950 hpa RAP RH and the local WRF.
The Northland saw visibilities come down overnight due to the
stratus, but there were few observations meeting true fog (less
than 1 mile). Tonight will likely be similar. However, there could
be some spots with foggier conditions wherever the stratus is low
enough, such as in higher terrain, so have patchy fog moving
inland tonight.
The model soundings are indicating a brief period of deepening
stratus from near the Twin Ports into the Arrowhead, near and
shortly after dawn tomorrow. The GFS even has a little
precipitation. Added patchy drizzle for this area because it looks
like the stratus layer might be deep enough to squeeze out a
little moisture.
Bands of cloud cover from the upper-level low will swing west
into the southeast forecast area late today into early Saturday,
and it might produce some very light rain for the far southeast
forecast area, near Prentice and Ogema.
.LONG TERM...(Saturday night through Friday)
Issued at 306 PM CDT Fri Sep 30 2016
The forecast area will remain positioned between low pressure
rotating to our south near Chicago, and high pressure anchored
to the north over Ontario into next week. The flow will turn
southerly and strengthen through the beginning of next week as the
next low pressure system advances into the Dakotas.
Latest runs of the GFS/ECM are in surprisingly good agreement with
the low that will impact the region next week considering its
out on day 5 and beyond. The long wave trough, with closed 500hPa
low, is projected make landfall on the western coast Sunday, then
migrate east across the central US and into the Northern Plains by
Wednesday. This track will allow for a warm front to lift over the
region early in the week, bringing a surge of warm gulf air along
with a chance for showers and thunderstorms with it. Once the low
passes over the western Lake Superior region and cold air
advection makes a return for the upcoming weekend, a much cooler
airmass with 850hPa temps well below zero will dive into the
Northland. This may be our first shot at light snow accumulations
along the borderland.
However, suspect overall timing of the long wave trough and
associated stacked low/precipitation chances will be slower than
currently in forecast. This is due to model bias of typically
progressing closed systems too fast, as well as the impact of the
tropical storm approaching the east coast during this time; which
the GFS and ECM are showing large differences with.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 645 PM CDT Fri Sep 30 2016
A ridge of high pressure was over the Northland with an easterly
surface flow. IFR ceilings over far western Lake Superior into
northern Wisconsin and far northeast Minnesota will expand toward
the west and north again tonight as the low level inversion
strengthens. There may be some fog that forms tonight with the
visibility restrictions lowest in the higher terrain along Lake
Superior.
The HRRR and RAP suggest the low clouds will dissipate on
Saturday by late morning or early afternoon. This occurs even near
Lake Superior per the latest HRRR/RAP. We followed those model
trends at KDLH and went VFR around 17Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 49 61 46 63 / 0 10 0 0
INL 44 66 47 69 / 0 0 0 0
BRD 48 65 46 69 / 0 0 0 0
HYR 49 66 45 66 / 0 0 0 0
ASX 49 61 47 64 / 0 0 0 0
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...Grochocinski
LONG TERM...Graning
AVIATION...Melde
Area Forecast Discussion
National Weather Service Flagstaff AZ
840 PM MST FRI SEP 30 2016
.SYNOPSIS...Expect quiet weather and near average temperatures on
Saturday, although a few light showers will be possible over
higher terrain. Increasing winds are forecast ahead of an
approaching low pressure system on Sunday, followed by strong
southwest winds and noticeably colder temperatures on Monday and
Tuesday.
&&
.DISCUSSION...
The scattered shower and isolated thunderstorm activity from this
afternoon and evening has ended and tonights forecast was updated to
capture this. Surface dewpoint depressions are at 5 degrees or less
at several sites this evening and will monitor as this may lead to
patchy fog development overnight.
&&
.PREVIOUS DISCUSSION 236 PM...On Saturday, northern Arizona will be
under the influence of high pressure. Most of northern Arizona is
expected to experience dry weather, near average temperatures and
partly cloudy skies. With that said, some model guidance suggests
there may be just enough low level moisture for a few showers.
Decided to go with a slight chance of showers over higher terrain,
although stable conditions may lead to the formation of an extensive
cumulus field and nothing in the way of precipitation.
On Sunday, things begin to change as a deep low pressure system
approaches the state from the northwest. While daytime
temperatures will remain near seasonal averages, breezy southwest
winds will foreshadow the passage of an unseasonably cold low on
Monday and Tueday. The newest GFS model run shows a south to north
oriented line of light showers crossing the region, likely in
response to a subtle increase in moisture and weak forcing from a
fast moving, low level thermal gradient. Decided to add slight
chance pop`s to the forecast during this time to account for this,
but confidence is very low at this point.
The bulk of the cold air arrives on Monday as the west coast low
crosses the state. Expect very strong southwest winds and a
noticeable drop in temperatures. Wind gusts in excess of 40 mph
will be possible. Daytime temperatures are expected to drop by
around 10 degrees as compared to Sunday at most places, which
would be around 10 degrees below average for this time of year.
The coldest low temperatures of the last several months are
forecast on Tuesday morning. A hard freeze will be possible above
6000 feet. Similar temperatures are forecast for Tuesday, with
winds weakening and shift to the northeast on heels of the
departing low.
On Wednesday and Thursday, a zonal flow pattern and a warming
trend are forecast in the wake of the departing weather system.
&&
.AVIATION...For the 06Z package...Dry weather is expected through
18z Sat then a slight chance of an isolated rain shower over the
high terrain of northern AZ. SW sfc winds 10-20kt btwn 17z sat - 02z
Sun otherwise light winds. Aviation discussion not updated for TAF
amendments.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...DL RR
AVIATION...DL
For Northern Arizona weather information visit
weather.gov/flagstaff
Area Forecast Discussion
National Weather Service Hastings NE
646 PM CDT FRI SEP 30 2016
.UPDATE...
Issued at 638 PM CDT Fri Sep 30 2016
Updated the forecast this evening to increase sky cover
significantly, due to the nearly solid shield of mid to upper
level sky cover that looks like it will hang around for several
hours. This could hold up temperatures from dropping off as fast,
but it appears that a late night clearing still looks plausible,
which will allow temperatures to take a quick drop by early
morning. This will probably hold off the fog development, but I
anticipate a potential quick hit of fog in our eastern/northeast
quarter of the CWA with light upslope flow. The HRRR seems to be
hitting this pretty hard, and I have hit wording a bit harder from
patchy to areas of fog for much of our east. Not looking for dense
fog, necessarily, considering that the shield of clouds should
give us quite a late start to fog development.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 323 PM CDT Fri Sep 30 2016
Satellite and observations show that cirrus has moved across the
forecast area through the day. Most of it is still thin enough that
the sun comes through, but there are clouds. The surface high that
has been over the area has moved to the east and winds are turning
to the south.
The surface high continues to move to the east tonight, but the
pressure gradient does not tighten so winds will continue to be
fairly light through the night. The light winds will allow
temperatures to fall off toward morning. Have kept the lower
temperatures, especially in the north where low temperatures have
been pretty cool.
Saturday the winds should remain fairly light since the pressure
gradient does not tighten much. They will be more from the south
during the day. There is some additional moisture that arrives on
the south winds and there will be a few more clouds. The main
question is whether there will be any precipitation. The NAM
continues to show some very spotty QPF, but there is less than the
previous runs have had and the WRF is dry. Will once again keep the
forecast dry.
.LONG TERM...(Saturday night through Friday)
Issued at 323 PM CDT Fri Sep 30 2016
Saturday night through Monday an upper level ridge will move across
the plains. Temperatures will warm up, with Monday being the warmest
day of the period. The pressure gradient is the tightest Monday and
the winds will be the strongest. The winds at 850mb are around 45
kts during the afternoon.
An upper level low moves through the Rockies and into the northern
plains Monday night through Wednesday. The main energy is to the
north with the upper low, but the trough moves through the forecast
area. At the surface, there is a surface low and cold front moves
into the forecast area Tuesday night. Thunderstorms are expected to
move into the forecast area during the night Monday night and spread
across the area. With the front in the area Tuesday and Tuesday
night, the best chances for thunderstorms will be Tuesday and
Tuesday night. The best chances will be in the east, ahead of the
front. There is MUCAPE of up to 1000 j/kg across the east during the
afternoon and evening. The thunderstorms could linger into Wednesday
before the trough moves to the east.
Wednesday night through Friday there will be northwest flow across
the area and a surface high settles into the area. This will bring
clearing skies and lighter winds. Temperatures will return to near
normal again.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday evening)
Issued at 638 PM CDT Fri Sep 30 2016
Main concern will be visibility as mid to upper level sky cover
should clear late night, allowing a drop in visibility with light
upslope flow.
&&
.GID Watches/Warnings/Advisories...
NE...None.
KS...None.
&&
$$
UPDATE...Heinlein
SHORT TERM...JCB
LONG TERM...JCB
AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Wichita KS
610 PM CDT FRI SEP 30 2016
.SHORT TERM...(This evening through Monday night)
Issued at 310 PM CDT Fri Sep 30 2016
Forecast highlights: Fairly quiet weather through Monday, with
shower/thunderstorm chances increasing Monday night- Wednesday
night. Quiet weather again by late week and next weekend.
Could see fog development later tonight into early Saturday
morning over portions of east-central and southeast Kansas, due to
light winds and clear skies atop surface ridge axis. RAP soundings
indicate potential for dense fog amidst a moistening boundary
layer, so evening shift will need to monitor.
Cannot rule out a few showers/thunderstorms west of I-135 Saturday
night into Sunday morning given increasing 850-700 warm advection
and moisture transport. Forcing and elevated instability are weak,
so not expecting widespread activity.
Otherwise, daytime temperatures will steadily warm through Monday
as southerly flow and atmospheric thickness gradually increase
ahead of a deepening western CONUS trough. Readings by Monday
should reach the 80s most areas, with stout/gusty south winds as
lee trough strengthens over the High Plains. Expecting
shower/thunderstorm chances to increase generally west of I-135
Monday night, as large scale ascent from deep western CONUS trough
and associated cold front approach from the west.
.LONG TERM...(Tuesday through Friday)
Issued at 310 PM CDT Fri Sep 30 2016
Per medium range model consensus, shower/thunderstorm chances
continue areawide Tuesday- Wednesday night, as the western CONUS
longwave trough and associated cold front moves across Mid-
America. Quite a bit of model spread regarding the evolution,
magnitude, timing and placement of various synoptic features, so
confidence on forecast specifics remains low. Despite moderate to
strong forcing and decent deep layer shear, thinking overall
threat for severe weather is on the low side throughout this event
given limited moisture return and associated poor instability.
Cooler and pleasant weather will return by late week in wake of
the cold front, with upper ridging building from the west.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 610 PM CDT Fri Sep 30 2016
Except for some patchy early morning fog potential in southeast
Kansas, VFR conditions will continue across the area with patchy
dense cirrus overhead. Winds will remain light as the stubborn
surface ridge axis slides very slowly east to the Missouri
border by Saturday afternoon.
Confidence is rather low on VSBYS dropping into the IFR category
at KCNU so for now will relegate mention to TEMPO MVFR.
KED
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 51 76 56 79 / 0 0 10 10
Hutchinson 50 76 54 78 / 0 0 10 10
Newton 50 74 54 77 / 0 0 10 10
ElDorado 51 75 54 78 / 0 0 10 10
Winfield-KWLD 51 77 55 80 / 0 0 10 10
Russell 49 76 53 79 / 0 10 20 20
Great Bend 50 77 53 79 / 0 10 20 20
Salina 49 76 54 79 / 0 0 10 10
McPherson 50 75 54 78 / 0 0 10 10
Coffeyville 50 77 53 80 / 0 0 0 0
Chanute 50 75 52 78 / 0 0 0 0
Iola 50 74 52 77 / 0 0 0 0
Parsons-KPPF 50 76 51 79 / 0 0 0 0
&&
.ICT Watches/Warnings/Advisories...None.
&&
$$
SHORT TERM...ADK
LONG TERM...ADK
AVIATION...KED
Area Forecast Discussion
National Weather Service Northern Indiana
723 PM EDT Fri Sep 30 2016
.SYNOPSIS...
Issued at 300 PM EDT Fri Sep 30 2016
An upper low near the Ohio River will begin to drift north
tonight and should be over northern Indiana Saturday afternoon.
Showers and a few storms are possible Saturday with lingering
showers possible into Sunday. Highs through the weekend will be in
the 60s with lows in the 50s. High pressure will bring slowly
improving conditions early next week.
&&
.SHORT TERM...(This Evening through Saturday)
Issued at 229 PM EDT Fri Sep 30 2016
Cold core upper low nr KEVV this afternoon will begin to lift ne
into sw OH by late tonight up twd KTOL by Sat evening. Primary nr
term focus resides invof of sfc occlusion through cntrl IN and north
across lower MI within mid lvl deformation zone and low level theta-
e ridge. Disorganized forcing in between suggests truncating prior
pops to no more than high chc going forward in line with 12Z mos
trends sans far south in proximity of sfc occlusion.
Otherwise northward pinwheel of mid lvl cyclone Sat along with more
focused mid level ascent should promote additional showers across
the ern half of the cwa.
&&
.LONG TERM...(Saturday Night through Friday)
Issued at 229 PM EDT Fri Sep 30 2016
Western flank of mid lvl deformation zone expected to wrap sewd into
the ern lakes Sun aftn as closed low accelerates newd through New
England. Will hold with low chc pop ern areas yet drop west as
fairly aggressive ll neg theta-e advection develops through the wrn
lakes.
Beyond that pattern reversal aloft develops as mid lvl ridge builds
in behind departing upper trough over New England with commensurate
ramp of ll thermal ridge through the Oh Valley. This will yield a
vigorous warming trend through mid week if not longer as new sys
lifting out of the wrn US slows its eastward progress upstream of
hurricane Matt.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 721 PM EDT Fri Sep 30 2016
(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 250 PM EDT Fri Sep 30 2016
Upper low still expected to meander northward this period and be
near Toledo by this time Saturday evening. Aviation forecast
difficult given variable cigs and scattered showers. Have timed
shra activity first several hours per latest hires guidance and
radar trends. Cigs expected to drop into IFR category overnight
with moist low levels and light wind field. HRRR developing some
LIFR Vis conditions due to fog...primarily near KFWA. For now
trended toward about a mile with BR and will have to monitor
conditions overnight to see if dense fog can form with thick cloud
cover still in place.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 11 PM EDT this evening for LMZ043-046.
&&
$$
SYNOPSIS...Skipper
SHORT TERM...T
LONG TERM...T
AVIATION...Lashley
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AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1125 PM EDT Fri Sep 30 2016
.UPDATE...
Issued at 1115 PM EDT FRI SEP 30 2016
Hourly temperatures have been updated based on recent observation
trends in the areas of clearing in between bands of clouds. This
led to dropping temperatures in few valley locations.
UPDATE Issued at 840 PM EDT FRI SEP 30 2016
An upper level low continues to spin over the OH Valley region.
However, significant breaks have developed across East TN north
into Eastern KY. This has allowed for some valley temperatures to
drop into the lower 50s. Only some minor adjustments were made
based on recent observations. The main changes were to the hourly
temperatures for valley locations over the next few hours.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 340 PM EDT FRI SEP 30 2016
18z sfc analysis shows a broad area of low pressure through the
Ohio Valley and Southern Appalachians. Most of East Kentucky is in
the southwest quadrant of this system and pretty much dry slotted
keeping the showers and any storms west and northeast of the CWA.
Plenty of clouds and morning fog slowed the temperature rise
through eastern Kentucky today, but with more clear breaks the
sunshine is helping to send temperatures into the low and mid 60s.
Meanwhile, dewpoints are running in the low 50s for most places
with the winds light and variable.
The models are in good agreement aloft with their handling of the
fairly deep closed low wobbling over the Ohio Valley through the
weekend. They all have the low tracking slowly due north with some
minor divergence in solutions late in the short term. The GFS
moves the low to the Great Lakes a notch quicker than the others,
but strength is similar from all models. They all, also, have
ample mid level energy rotating through the low over head. Given
the agreement will favor a blended solution with the HRRR and
NAM12 leaned toward in the near term.
Sensible weather will feature another cool evening and overnight
as the clouds partially break up. This will make for varying
amounts of radiational cooling and better radiational fog
formation at times overnight. The latest CONSShort guidance keeps
the more extensive and thickest fog just to the west of the CWA
tonight. For this reason, will allow some mainly valley fog in
the grids toward midnight and through dawn with some locally dense
patches in the deeper valleys toward 12z. The next pinwheel of
energy aloft may bring some light showers to western parts of the
CWA overnight and into Saturday morning, but most of the area
should remain dry. Look for the fog to burn off Saturday morning
and a bit more sunshine should allow for temps to reach the upper
60s to low 70s most places. Similar conditions are anticipated
Saturday night with more valley centric patchy fog late. Also,
a couple stray showers may move in late Saturday into Sunday
morning as the upper low and sfc low start to move out.
Again used the CONSShort and ShortBlend as a starting point for
most grids into Saturday morning with the SuperBlend used
thereafter. Made only minor changes to the T grids based on our
terrain with the clouds around. As for PoPs - ended up on the low
side of a MOS blend through Sunday morning.
.LONG TERM...(Sunday through Friday)
Issued at 248 PM EDT FRI SEP 30 2016
The forecast for the extended should feature isolated rain showers
moving across eastern Kentucky, as an area of low pressure aloft
moves across the lower Ohio Valley region on Sunday, a period of dry
and pleasant weather, and possibly another round of rain Thursday
night into early Friday. A cold front would be the trigger for any
rain we may see toward the end of next week. Temperatures during the
period are expected to max out in the 70s each afternoon, and bottom
out in the 50s each night. A few spots may reach or slightly exceed
80 degrees Tuesday through Thursday, mainly along and south of the
Hal Rogers Parkway and Highway 80 corridor.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 830 PM EDT FRI SEP 30 2016
An upper level low continues to meander across the Lower OH
Valley. This will lead to band of clouds through the period and
the threat of mainly diurnally driven isolated showers. The degree
of clearing remains uncertain, but at least some dense valley fog
is anticipated. However, confidence in the location and duration
of cloud cover is not high at this time. At this time, the TAF
sites are still expected to be limited to mainly MVFR vis
restrictions for a few hours between 8z and 13z. Mainly vfr
should then prevail through the end of the period with the
exception of brief mvfr possible in any isolated showers. Winds
will remain light and variable through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JP
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1016 PM CDT FRI SEP 30 2016
.UPDATE...
Issued at 843 PM CDT Fri Sep 30 2016
Persistent pattern continues this evening with clouds along with
scattered showers rotating through IL and the eastern half of MO
on the backside of slow moving upper level and surface low over
southern IN. Looking at the latest radar trends it appears that
scattered showers, mainly on the light side will continue for the
rest of the evening along and east of the Mississippi River. The
latest HRRR model runs diminishes this activity by midnight, but
still could not rule out isolated light showers or patchy drizzle
late tonight across west central and southwest IL. Low level
cloud deck should keep temperatures from getting too cool tonight
with lows similar to the previous night and slightly above normal
for the beginning of October.
GKS
&&
.SHORT TERM... (Through Late Saturday Afternoon)
Issued at 300 PM CDT Fri Sep 30 2016
Upper low will begin to slowly lift to the north northeast late
tonight. In the meantime, isolated/scattered showers to continue
rotating counter clockwise across forecast area with best chances
along and east of Mississippi River through Saturday. Some isolated
thunderstorms not out of the question for Saturday afternoon, mainly
for our far eastern counties, so kept in grids in this area. With
the clouds lingering over the region, lows tonight will be a few
degrees warmer. However, highs on Saturday to remain below normal,
in the upper 60s to low 70s. As for winds, to lighten up and back to
the northwest by midday on Saturday as upper low moves away from
region.
Byrd
.LONG TERM... (Saturday Night through Next Friday)
Issued at 300 PM CDT Fri Sep 30 2016
The pesky upper low will be on the move during the first part of
this period, lifting into the lower Great Lakes by early Sunday
morning and the northeastern U.S. by early Monday. As it departs
we will see a lessing influence manifested by weakening low level
cyclonic flow and eventually the dominance of lower tropospheric
high pressure by Sunday.
I have kept some slight chance pops on Saturday evening to the
east of the MS River where there could be lingering diurnal
activity from the day. I have concerns that we may settle into a
period from Saturday night into early Monday with extensive clouds
trapped within the low level ridge. And if locations do clear out
during the day, then fog/stratus will have a tendency to redevelop
at night. SREF probabilities suggest this to a degree, and I think
the light QPF evident in some of the deterministic models for
Sunday is a reflection of the low level moisture and clouds. I
have boosted clouds quite a bit during the Saturday night-Monday
morning time frame, especially Saturday night-Sunday where greater
confidence lies. Accordingly I have also lower high temps a tad.
The deterministic and ensemble model soutions are in relatively good
agreement with the large scale pattern change this weekend into
next week as a progressive longwave trof moves out of the western
U.S. and into the Nation`s midsection in the Wed-Thurs time
frame. This pattern change will result in a retreat of the low-
level ridge Monday-Tuesday, slight height rises aloft followed by
increasing southwest flow aloft, and evolution of a low level WAA
regime. In terms on sensible weather there should be moderation of
temperatures Monday into Tuesday, with a cold front moving into
and through the area somewhere in the Wednesday-Thursday period.
There are differences in timing/speed of the attendant cold front
due to presence or lack of a trailing shortwave trof Thurs/Thursday
night. The ECMWF is faster and wetter late Wed/early Thurs period,
while GFS with the trailing shortwave scenario is slower with main
round of precipitation Thurs/Thurs night.
Seasonably cool and drier weather should then dominate Friday into
next weekend as the upper trof dampens out and passes to the east
with west-northwest flow aloft dominating the pattern aloft.
Glass
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 958 PM CDT Fri Sep 30 2016
Low level clouds along with scattered showers continue to rotate
through eastern MO and IL on the backside of the slow moving upper
level and surface low over southern IN. Most of the showers should
be east of the taf sites late tonight, although could not rule out
a brief light shower or a little drizzle in UIN and the St Louis
metro area. The cloud ceiling will gradually lower overnight into
the MVFR catagory in COU and into the IFR catagory in UIN and the
St Louis metro area. The cloud ceiling should gradually rise into
the VFR catagory by late Saturday afternoon with daytime heating
and mixing and deepening of the boundary layer. May be a few
showers Saturday afternoon in UIN and the St Louis metro area.
North-northwesterly surface winds will continue through the
period.
SPECIFICS FOR KSTL: Low level clouds along with scattered showers
continue to rotate through eastern MO and IL on the backside of
the slow moving upper level and surface low over southern IN. Most
of the showers should be east of the taf sites late tonight,
although could not rule out a brief light shower or a little
drizzle in the STL area. The cloud ceiling will gradually lower
overnight into the IFR catagory in STL. The cloud ceiling should
gradually rise into the VFR catagory by late Saturday afternoon
with daytime heating and mixing and deepening of the boundary
layer. May be a few showers Saturday afternoon in STL. North-
northwesterly surface winds will continue through the period.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
740 PM EDT Fri Sep 30 2016
.SHORT TERM...(This evening through Saturday)
Issued at 416 PM EDT FRI SEP 30 2016
WV imagery and RAP analysis indicated a mid/upper level low over far
srn Indiana and a ridge from the srn plains to the upper MS valley
and nrn Great Lakes. Radars indicated rain over much of the srn half
of lower MI associated with 700-300 mb qvector conv and 305-310k
isentropic lift to the north of the low. Some light showers or
sprinkles were also approaching MNM but had largely dissipated as
they moved into drier air and away from the stronger forcing.
Otherwise, mid clouds were gradually spreading into the srn cwa.
Diurnal stratocu had also developed over the cntrl cwa.
Tonight, expect light showers to continue to spread gradually to the
northeast with the potential for sct/isold -shra/sprinkles over the
srn cwa. With only weak forcing and a dry layer below 750 mb,
confidence is low with how far north any measurable pcpn will
develop. Increasing clouds will keep temps from falling off as much
with min readings from the upper 40s to mid 50s, coldest inland
west. Even though there is still enough low level moisture,
afternoon dewpoints in the mid 50s, to support patchy fog
development the clouds will reduce fog potential over the south and
east.
Saturday, with the mid level low drifting northward to far ne
Indiana by 00z/Sun, showers potential will also expand across the se
half of Upper Michigan. However, since the stronger forcing remains
farther to the se, only chance pops were mentioned. Despite the
thicker clouds over the area, high temps will remain above normal
with highs in the low to mid 60s.
.LONG TERM...(Saturday night through Friday)
Issued at 334 PM EDT FRI SEP 30 2016
Deep mstr arnd a slow moving closed lo pres in the Lower Lks could
cause some showers over the se half of Upr MI on Sat ngt into Sun,
but then an upr rdg shifting into the area wl bring dry wx into at
least Wed. The biggest uncertainty wl be on sky cover/potential for
lo clds during this time. As the cold fnt ahead of a deep, slow
moving wrn trof moves toward the area, shower chcs wl return later
in the week. Unseasonably warm air wl dominate the Upr Lks until
late next week, bringing continued above normal temps to Upr MI.
Sat ngt/Sun...Closed upr lo over far srn Lower MI on Sat evng is
fcst to lift slowly to the ne and thru far se Ontario on Sun.
Although the models are consistent showing a good deal of mstr
extending into the Upr Lks within the deep cyc ne flow on the nw
flank of this disturbance, the bulk of the larger scale deep lyr
cnvgc is progged to remain mostly to the se closer to the track of
the closed lo and impact only the ern portion of the cwa. Even this
forcing is progged to exit to the e on Sun as the closed lo drifts
in that direction away fm Upr MI. So the fcst wl continue to show no
more than chc pops over the se half, hiest on Sat ngt toward the
LOT/APX cwas and diminishing on Sun. Expect temps thru the weekend
to remain above normal, especially on Sat ngt with lots of clds in
the presence of h85 temps arnd 9C. The best chc for more sunshine on
Sun wl be over the w closer to slowly aprchg hi pres rdg axis if lo
clds associated with persistent near sfc mstr in that area do not
linger. Max temps on Sun should run mainly in the 60s even though
more persistent clds toward the e wl limit insolation.
Sun ngt into Wed...As the upr rdg to the e of a deep wrn trof shifts
into the wrn Great Lks early next week, a sfc rdg axis extending
swwd fm a hi pres center drifting fm over Hudson Bay into Quebec wl
dominate the Upr Lks. On Tue and Wed, this rdg wl shift the e,
causing a tightening pres gradient/strengthening sly flow over the
cwa to the e of falling mslp in the Plains associated with the
slowly progressive wrn upr trof. While dry wx wl prevail during
this time with larger scale subsidence under the upr rdg, some of
the medium range models have hinted at some lo clds/fog under
strengthening subsidence invrn with lgt ne winds off Lk Sup on Mon
and then the sly flow off Lk MI on Tue/Wed at a time of the year
dominated by lowering sun angle/diminished daytime mixing/longer
nocturnal cooling. The potential for this lo cld cover is the
biggest uncertainty during this period. Fcst h85 temps arnd 9C
rising toward 12C on Wed wl ensure temps run abv normal during this
time, but the presence or not of lo clds would alter the min/max
temp anomalies and diurnal ranges. Best chc for anomalously warm
daytime max temps wl be on Tue/Wed in the downslope areas near Lk
Sup, where the prospect for more sunshine wl be greatest and
could lift daytime max temps aoa 70.
Wed thru Fri...Although there remain some timing differences on how
quickly the wrn trof and cold fnt attendant to associated lo pres
lifting into scntrl Canada wl move toward the cwa, shower chcs wl be
on the incrs on Wed/Thu as this fnt/warm conveyor belt mstr ribbon
aprch. Some of the longer term guidance generates a good deal of
pcpn over the area, not out of the question considering pwats fcst
to rise as hi as about 1.50 inches under the warm conveyor belt and
relatively slow ewd progression of the features that would extend
residence time of the stronger sly flow/deeper mstr. On the other
hand, some of the models show the more sgnft hgt falls passing to
the nw with lighter pcpn over the wrn Great Lks. Considering these
important differences, ll not deviate fm the consensus fcst.
Following the eventual cold fropa, looks like much cooler air wl
invade the area late in the week. The 00Z ECMWF shows one of the
coolest scenarios with h85 temps dipping blo 0C by late Fri and
supporting some lk enhanced pcpn under lingering moist cyc nw flow.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 735 PM EDT FRI SEP 30 2016
Expect VFR conditions at both CMX and SAW through the forecast
period. LIFR stratus will continue at IWD in upslope ne flow and
clear skies into the overnight hours could allow for fog to form with
the potential for a few hours of LIFR to VLIFR visibility possible.
Diurnal heating/mixing will allow conditions to improve to VFR at CMX
by early Saturday afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 416 PM EDT FRI SEP 30 2016
A weak pressure gradient across Lake Superior through the weekend
and early next week will keep east to northeast winds at 20 kts or
less. South-southeast winds may increase over 20 kts Tue into Wed
ahead of front moving out the Northern Plains. Strongest winds would
be over north central and eastern Lk Superior.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...- None -
LONG TERM...KC
AVIATION...Voss
MARINE...- None -
Area Forecast Discussion
National Weather Service Bismarck ND
355 AM CDT Sat Oct 1 2016
.SHORT TERM...(Today and tonight)
Issued at 355 AM CDT Sat Oct 1 2016
Warm, above-normal temperatures and plenty of sunshine will greet
western and central ND for the first day of October today.
As of 08 UTC, a few light showers continue over east central ND in
association with a modest shortwave trough and related vorticity
maximum. Overnight rapid-refresh guidance (the RAP and HRRR) has
been accurately assimilating observed radar trends and has been
rather steadfast in calling for the showers to diminish by 12 UTC
as the vorticity maximum shears northeastward. That expectation is
supported by recent satellite imagery, which shows both deep-layer
drying and resultant clearing advancing east across the Highway 83
corridor at this hour.
In the wake of the early-day shortwave trough, flow aloft will be
rather lackluster between the 500-mb low drifting around the Great
Lakes region and a deepening trough approaching the northwest U.S.
coastline. The result will be a sunny afternoon, and model-derived
soundings from both coarser-scale guidance like the 00 UTC GFS and
NAM and higher-resolution simulations like the HRRR that have more
sophisticated boundary layer parameterization schemes all support
rather uniform mixing to about 850 mb this afternoon. Despite weak
flow aloft, mixing to that level in the face of seasonably strong
diabatic heating supports highs on the warmer side of the guidance
envelope today, especially since soils and vegetation are drying.
We are thus calling for highs well into the 70s F, with lower 80s
F expected in parts of western ND. Southerly winds in the boundary
layer are forecast to peak between 15 and 20 kt, lower than in the
last few days, so while there will be a bit of a breeze, it won`t
be windy by any means.
Tonight, a weak shortwave trough that is forecast to generate some
convection in central MT this afternoon and evening will approach
western ND. However, we maintained a dry forecast area-wide since
the 00 UTC multi-model consensus didn`t provide much support for
the remnants of that activity reaching the state before daybreak.
Lows will be mild for this time of the year, mainly in the lower
50s F.
.LONG TERM...(Sunday through Friday)
Issued at 355 AM CDT Sat Oct 1 2016
The focus of the long term forecast is on potential impacts from a
powerful upper-level trough and accompanying strong surface low
which is expected to cross the region next week. However, based on
recent trends in deterministic and ensemble guidance, it appears
that the heaviest precipitation with this system may end up being
west of the area, across MT.
Mid-level lapse rates are forecast to gradually steepen Sunday and
Sunday night, which will yield an uptick in instability and thus a
chance of showers and thunderstorms is in place as the flow aloft
takes on a more definitive southwest trajectory. However, taken at
face value, the 00 UTC GFS, NAM, and ECMWF suggest that the chance
of convection will be minimized by 1) an early-day timing of the
weak shortwave trough Sunday, before diurnal instability has had
an opportunity to increase, and 2) increasing amounts of MLCIN for
elevated parcels on Sunday night.
A greater chance of precipitation, including the risk of strong to
isolated severe thunderstorms, is expected Monday and Monday night
when strong height falls occur aloft as a 500-mb low reaches south
central MT. Boundary layer dewpoints in the middle to upper 50s F
as forecast by the normally-well-verifying 00 UTC NAM would yield
afternoon and early evening MLCAPE of 500-1200 J/kg and increasing
southerly flow aloft will yield 0-6-km bulk wind shear of 40-50 kt
by early evening, especially in southwestern ND. This may produce
organized storms, and indeed most NAM soundings are analogs to at
least marginal severe storm environments even though the flow is
forecast to lack much directional shear above 1 km.
Thereafter, the 00 UTC GFS and its ensemble members made a strong
move in the direction of the 12 and 00 UTC ECMWF in calling for
the 500-mb low to lift from eastern MT into southern Saskatchewan
with a prominent dry slot across most of western and central ND on
Tuesday and Wednesday. We stayed the course with the multi-model
consensus for our precipitation forecast, maintaining chance-type
PoPs in that period since the trough is still offshore and thus
its track is far from set in stone. Having said that, the 00 UTC
GFS ensemble made a dramatic shift toward a drier scenario across
western and central ND. For example, only one of its members has
more than one-half inch of QPF at Bismarck whereas the 12 UTC GFS
ensemble had a mean QPF of almost an inch. While the GFS ensemble
tends to be under-dispersive, this signal is certainly noteworthy.
If this trend continues, it`s possible the biggest impact with
this system may actually be the cold air advection in its wake,
which could yield a freeze by Thursday night/Friday morning if
the 00 UTC GFS and its MOS-based output is correct.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 355 AM CDT Sat Oct 1 2016
VFR conditions are expected at all TAF sites for the 06Z period.
Low level wind shear remains possible across the south central
(KBIS) through 12Z this morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...NH
Area Forecast Discussion
National Weather Service Cleveland OH
308 AM EDT SAT OCT 1 2016
.SYNOPSIS...
Low pressure over the lower Ohio Valley will lift north into
lower Michigan by Sunday then shift east of the forecast area on
Monday. A large area of high pressure will move across the Great
Lakes Monday and move off the New England Coast late Tuesday.
&&
.NEAR TERM /THROUGH TODAY/...
The precip coverage over the area has diminished as advertised by
the HRRR and other guidance. Much of the morning hours could be
dry but a few stray showers will likely persist. Will keep small
chance pops going this morning since I am not comfortable going
completely dry with a potent upper low parked over the region.
Expect the coverage to increase this afternoon as another lobe of
moisture rotates across the area. Similar to yesterday the brunt
of the precip today will likely be in the east and north ends of
the area. Cannot rule out a few rumbles of thunder so will keep
that mentioned as well. QPF totals are again a challenge with
many areas seeing under a tenth of inch today but a few possibly
seeing an inch. Looking at yesterday temps and considering the
amount of clouds and precip expected today will undercut guidance
temps for highs.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
The upper low will finally start to pull off on Sunday but it will
take till midday Monday before it`s impact on the local area is
finally over. More showers are expected tonight with perhaps the
greatest coverage of the entire three day event. Have bumped
precip chances up and would have liked to have gone higher but had
to match up with neighboring offices. By Sunday afternoon most of
the showers will be over the northeast half of the area and by
late Sunday night only some scattered showers are expected in the
far east. Skies will gradually clear in the subsidence behind the
upper low. Temps Sunday will continue on the cool side with
seasonable readings on Monday. Tuesday is shaping up to be a nice
day for early October with abundant sunshine and readings in the
lower 70s.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
Models differ some on how fast next upper trough can push ridge off
to the east and thus how fast surface cold front can arrive with
next chance for rain. Generally sticking with superblend with
increasing pops for thu into thu night then lingering chance on fri.
Above normal temps for wed and thu should drop close to normal by
fri as cooler air starts to arrive.
&&
.AVIATION /06Z Saturday THROUGH Wednesday/...
Upper and surface low in srn indiana will be slowly lifting north
thru 06z tonight causing east winds of 5 to 15 knots to turn toward
the south. Mix of mostly vfr and mvfr conditions should generally
lower to mix of mainly mvfr and ifr by end of the night then improve
to mainly vfr by midday today as daytime heating occurs. Sct shra
with isold tsra will continue.
OUTLOOK...Non-VFR in showers and low ceilings at times into
Monday.
&&
.MARINE...
Weakening low lifting north thru indiana into michigan will allow
winds to continue to diminish some this morning while veering toward
the south then sw today into tonight. As the low moves off to the
east sunday night into monday...winds veer to west then nw while
speeds generally stay 10 knots or less. High pressure builds in from
the north monday causing winds to continue to veer to the ne late
monday into monday night then more to the east for tue and wed as
the high shifts east of the lakes.
With the upper low creating a good temp differential on sunday there
is a potential for waterspouts to occur so this may need to be added
to forecast at some point over the next 24 hours.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EDT early this morning for
LEZ142>147.
&&
$$
SYNOPSIS...Kubina
NEAR TERM...Kubina
SHORT TERM...Kubina
LONG TERM...Adams
AVIATION...Adams
MARINE...Adams
Area Forecast Discussion
National Weather Service State College PA
540 AM EDT Sat Oct 1 2016
.SYNOPSIS...
A cut off upper low over the Ohio Valley will drift slowly to the
northeast over the next few days, clearing the region by early in
the upcoming week. A ridge of high pressure will build east into
Pennsylvania behind this system and will likely remain over the
area through the middle, and perhaps end of the work week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Early morning IR/water vapor loop shows the cut off upper low
spinning over the Lower Ohio River Valley. Deep, moist east-
southeasterly flow ahead of this system continues to produce thick
stratus with areas of drizzle and higher elevation dense fog
across central Pa as of 09Z.
Primary shortwave and associated right entrance region of the 90
kt southerly 300 mb jet will support widespread drizzle and
periods of light to mdt rain across the western half to two-thirds
of the forecast area through the late morning hours. Rainfall
will average one tenth of an inch or less through 15z. However,
locations seeing a couple of heavier showers (especially over the
NW mtns) could pick up 3-4 tenths of rainfall in just a 15 to 30
minute period.
Much of region east of the Middle and Lower Susq Mainstem will
stay dry this morning, with just some patchy drizzle or a brief
shower.
Temperatures will start out the day in the lower 50s across the
mountains of northern and western Pennsylvania, and mainly in the
mid 50s elsewhere.
Another murky day is expected across central PA today, as low lvl
(sfc-900 mb) easterly flow should keep nearly all of central Pa
under low stratus throughout the day. The morning/early afternoon
hours should see the greatest coverage of shower activity across
the western mtns, then a decreasing chance of showers from sw to
ne during the mid to late afternoon hours there.
06-08Z runs of the HRRR (and the mean of the 00Z-06Z NAM) shows a
nearly north- south ribbon 850 mb-based lifted indices in the -2
to -3C range forming from near KOLE to KUNV and KHGR in the 17-20z
period as the leading edge of cooling in the 700-500 mb layer
approaches from the west and the shield of thicker/high clouds
peels off to the east.
Although the near sfc layer will stay stable today, 925-850 mb
lifted indices will dip below zero across the region to the
southeast of the I-99/I-80 corridors this afternoon. This will
support a slight chc for a few elevated TSRA that will track
generally northward within some enhanced/fairly narrow bands of
showers. The western edge of this more focused area of showers and
isolated embedded TSRA should be near a KELZ to KSEG and KMDT/KLNS
LINE between 21-23Z.
Rainfall for the 12Z Sat-00Z Sun period will be a tenth or so in
many locations. places that see a few heavier showers and a brief
thunderstorm could see 0.25 to 0.50 inch of rain. The best chc for
these higher amounts would be across the region bounded by a line
from KELZ to KUNV...KMDT...KAVP...and KELM.
Blended model guidance (NBM) once again appears to warm and
unable to adequately handle the shallow/cool easterly llvl flow
and low clouds that will stay trapped in the ridge and valley
region and across the nrn mtns for much of the day.
EC and NAM guidance is 5-8 deg F cooler (and up to 10 deg F in a
few locations) than the most recent, 30/00Z and 12Z National
Blend of Models for most locations in our CWA today. Will keep
forecast max temps nudged closer to this cooler guidance. Highs
this afternoon will only make it to the upper 50s across the
mtns...and lower to mid 60s elsewhere.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
Skies will stay mostly cloudy to cloudy tonight (mainly in the
form of stratus) as a near sfc easterly flow persists. Isolated
to scattered showers (and some patchy drizzle along the eastern
slopes and ridge tops will occur as one disturbance aloft exits
to the northeast of the region, and another upper 90-95 kt jetlet
moves into western PA early Sunday morning.
Rainfall amounts will be generally a few hundredths of an inch at
best in most places...with around one tenth possible in a few
locations. Similar low temps are anticipated tonight - in the
lower 50s across the northern and western high terrain, and mid to
upper 50s in the central and southern valleys.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Latest operational models track the persistent and slow-moving
cut-off low to near Detroit at 12z Sunday, before it finally
begins to turn east and gradually fills in as it gets picked up in
the longwave flow and tracks across NY state Monday.
The results on the forecast will be a continuation of showery
weather through the second half of the weekend, though with just
light amounts. Followed by a slight chance for showers across the
north early next week along with cold air advection filtering into
the region early next week.
Surface high pushing the cooler air our way slides off the New
England coast midweek, but persistent easterly flow feeding into
the Mid-Atlantic region should keep plenty of clouds around along
with at least a chance for light showers/drizzle across southern
half of CWA through midweek.
Latest on Hurricane Matthew in the 00z runs - Tremendous
differences have developed between the ominous GFS and the much
more benign forecast by the latest EC for the U.S. main-land.
The 00Z GFS brings a potent Matthew across the Western Bahamas
then has it paralleling the SE U.S. and Carolina coast late in
the week...before projecting it to get captured by a deepening
upper trough and accelerating north into Long Island next Sat/Sat
night. GEFS has roughly the same track, but as expected becomes
more diffuse through time with the location and intensity of the
storm`s center just off the East Coast.
The 30/12z operational ECMWF parked the storm over or just to the
north of the Bahamas for a prolonged period during the middle to
latter part of the upcoming week, which was a low confidence
solution.
The latest 01/00Z run of the EC now carries the hurricane well to
the northeast of the Bahamas Friday and on a steady course to the
Northeast toward Bermuda by the middle of next weekend. With such
drastic differences between the GFS/GEFS and the EC 5-7 days out,
we`ll continue to play the middle of the road and note just
scattered showers with the passage of a more definitive northern
stream shortwave and sfc cold front late next week or early next
weekend.
Temperatures will be slightly below normal through the latter half
of the weekend, before shifting to slightly above normal by the
middle of next week...then possibly dipping back to near normal as
clouds (at least the mid and high variety) thicken-up to the NW of
Matthew.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
Widespread IFR conditions will continue into tonight with
periods of -RA/BR/DZ. Gradual improvement to MVFR/VFR is
projected by later Sunday.
Outlook...
Sun...IFR trending to MVFR/VFR. Sct -shra.
Mon-Tue...Gradual improvement likely.
Wed...Mainly VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Fitzgerald/Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert
LONG TERM...Lambert/RXR
AVIATION...Steinbugl
Area Forecast Discussion...CORRECTED
National Weather Service Duluth MN
429 AM CDT SAT OCT 1 2016
.SHORT TERM...(Today through Sunday)
Issued at 419 AM CDT Sat Oct 1 2016
The cut off upper low over the Lower Ohio river valley early this
morning, along with a weak ridge axis extending over northern
Minnesota will remain in control of weather for the Northland
through the weekend. The upper low will gradually move north across
Indiana today, then slowly ease northeast into far southeast Ontario
by Sunday afternoon. This low is going to do little more than
bring some mid and high clouds to the eastern sections of the
forecast area through Sunday, with some small rain chances for
Price county. Stratus that has developed over the area downstream
of Lake Superior the last few mornings is here once again, with
the relatively warmer -mid 50s- lake modifying the airmass that is
in the mid 40s where the clouds are clear. Expect this behavior
once again tonight, with stratus developing over the head of the
lake and over the Bayfield Peninsula in the lee of the light east
to northeast flow over the lake. The signal is not as strong as it
was the last two nights, but the pattern is about the same, and
there really hasn`t been significant change in the airmass, so it
seems best to assume the stratus will form again. The similar
airmass and only small changes in cloud cover should favor a
persistence forecast in temperatures, with highs both days getting
into the middle and upper 60s and upper 50s/low 60s near the lake.
Onshore flow is weaker on Sunday so it should be a little warmer
near the lake then. Lows to be very similar as well, dipping into
the low 40s where it clears out, with mid and upper 40s under the
cloud cover.
.LONG TERM...(Sunday night through Friday)
Issued at 419 AM CDT Sat Oct 1 2016
Sunday evening continues the long-awaited departure of the
stagnant cut-off low. By 03.00Z, that feature is forecast to be
over the eastern Great Lakes and progressing eastward with time.
Farther to the west, a high pressure ridge will be positioned over
the Plains and the Upper Midwest. A weak shortwave trough is
forecast to move across the northern Canadian Prairie Provinces
overnight and early Monday. Surface high pressure over the western
Great Lakes, with the transient low to the north, will continue
the development of a southerly return flow across the region
Sunday night into Monday.
The upper-level ridge will advance eastward ahead of a deepening
longwave trough digging across the western United States by Monday
night. A cold front will push across the Dakotas and into western
Minnesota overnight with increasing cloud cover and rain showers
spreading east toward the Northland. Tuesday afternoon through
Wednesday evening appear quite soggy with and area of rain, and a
few embedded thunderstorms, slowly moving eastward ahead of the
decelerating cool front. Twenty-four hour rainfall of 1 to 2
inches seems likely for the eastern two-thirds of my CWA.
Differences in the deterministic and ensemble guidance increase
after Wednesday. The variety of solutions for the track and
intensity of Hurricane Matthew, and the resultant quasi-Rex Block,
produce a wide spread of sensible weather for the area. The
deterministic GFS brings the closed upper low slowly northeastward
into southern Manitoba by Thursday morning with most of the GEFS
members farther west. The ECMWF and GEM both feature a more
progressive solution with the ECMWF opening the low back into a
trough. Prefer the slower GFS solution and nudged the consensus in
that direction.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1240 AM CDT Sat Oct 1 2016
A ridge of high pressure will remain over the Northland through
the period. IFR/LIFR conditions were expanding over northeast
Minnesota and were diminishing in spots over northwest Wisconsin.
The RAP and HRRR forecast the stratus to continue to expand across
much of northern Minnesota overnight in the easterly low level
flow. They also show a lower chance of those ceilings over
portions of northwest Wisconsin including KHYR. We do expect some
fog will be possible at KHYR and perhaps some IFR ceilings and we
included a mention from 09-12Z.
The stratus is expected to gradually lift and dissipate through
late Saturday morning or early afternoon. An upper level low
pressure the Ohio Valley will lift north and cause VFR ceilings to
increase over portions of the Northland later tonight into
Saturday and they will be most likely at KHYR.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 63 45 65 46 / 10 0 0 0
INL 66 49 69 48 / 0 0 0 0
BRD 68 46 69 49 / 0 0 0 0
HYR 69 44 67 44 / 0 0 0 0
ASX 62 47 64 44 / 0 0 0 10
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...LE
LONG TERM...Huyck
AVIATION...Melde
Area Forecast Discussion
National Weather Service Lincoln IL
329 AM CDT SAT OCT 1 2016
.SHORT TERM...(Today and tonight)
ISSUED AT 324 AM CDT Sat Oct 1 2016
Short term will still be dominated by the slow moving low pressure
system just east of Illinois. The upper low center is expected to
gradually lift north through eastern Indiana today, while the
surface low center generally remains in western Indiana along the
Illinois border. Various lobes of energy are depicted to rotate
around the upper low through the day, with plenty of low level
moisture available to produce periodic rain showers and drizzle.
Low clouds, fog and drizzle will start the day, with periods of
heavier drizzle or showers at times the rest of the day. While the
better chances appear to reside in eastern Illinois, showers look
to hold together into western Illinois per the latest HRRR and RAP
model updates. Rainfall amounts should generally remain less than
a quarter inch, with most locations around a tenth of an inch. The
potential for thunder looks low, but a few rumbles of thunder
could develop this afternoon east of I-57. Diurnal temperature
swings will be held in check by the overcast skies, as high temps
only climb 10 to 12 degrees above morning lows. Highs should reach
the upper 60s to around 70 today.
Tonight, showers and drizzle should dissipate overnight, as the
surface and upper lows pull farther away to the northeast. Stratus
clouds will likely linger through at least Sunday morning. Patchy
fog will be possible as well, due to plenty of boundary layer
moisture. Low temperatures will be in the middle 50s.
&&
.LONG TERM...(Sunday through Friday)
ISSUED AT 324 AM CDT Sat Oct 1 2016
Large 564 dm 500 mb low over southeast Indiana will lift up
toward Detroit by sunrise Sunday, and into nw NY by dawn Monday.
IL will still be in a cyclonic flow on Sunday, as upper level low
pulls way from the region, though chances of rain showers to lift
ne of CWA on Sunday. Mostly cloudy skies expected most of the day
Sunday, though skies could become partly sunny during Sunday
afternoon especially sw of I-74 as nw winds bring in some drier
air. Highs around 70F from I-74 northeast and in the lower 70s sw
of I-74 on Sunday. Partly cloudy skies Sunday night with lows in
the low to mid 50s as weak surface high pressure ridge settles in.
Upper level ridge moves into the Great Lakes region on Monday and
provides a nice day to central/southeast IL with partly to mostly
sunny skies, light winds and seasonable highs in the low to mid 70s.
Fair skies Monday night with lows in the mid 50s. Upper level ridge
shifts east into New England on Tuesday, while cutoff upper level
low off the Pacific nw coast tracks into the northern high plains.
Another nice early fall day expected for IL with mostly sunny skies
on Tue and southeast winds bringing milder highs in the upper 70s.
Dry conditions expected to continue through Tue night with lows in
the upper 50s to around 60F.
00Z models still differ with movement of cold front eastward across
IL around Thursday. ECMWF model is keep CWA dry yet on Wed, while
GEM brings qpf into the IL river valley and GFS has qpf as far east
as I-55. Category 5 Hurricane Matthew with winds of 160 mph at 13.3N
and 72.5W is forecast to track northward into the Bahamas during Wed
and this may tend to slow the upper level trof and cold front west
of IL then. Have dry conditions over IL on Wed and 20-40% of showers
and thunderstorms by Wed afternoon from I-55 west with highest pops
of 30-40% nw of IL river. Highs in the upper 70s west of the IL
river on Wed with lower 80s east of the IL river. Have increasing
pops from west to east during Wed night with approaching of cold
front, with likely pops over IL river valley. Then this cold front
appears to move over IL on Thu as it weakens somewhat. Continued 40-
50% pops on Thu with highs in the lower 70s over IL river valley and
upper 70s over the Wabash river valley. Temps continue to cool
behind the front on Fri/Sat with highs in upper 60s/lower 70s on Fri
and mid to upper 60s on Sat. Dry conditions expected Fri and
Saturday with surface high pressure moving into from the west.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1100 PM CDT Fri Sep 30 2016
Pattern stuck in neutral over the Midwest with a large upper low
over extreme southern Indiana expected to bring IFR to LIFR
conditions to the forecast area again overnight into Saturday
morning. As the low shifts north through Indiana, the shower
threat will hold over the area thru the afternoon with a typical
lifting of the cigs during the afternoon to MVFR or low VFR.
As the low shifts away from our area tomorrow night, MVFR cigs
are expected to continue. Surface winds will be generally from
a northwesterly direction at 7 to 12 kts through the period.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
330 AM CDT SAT OCT 1 2016
.SHORT TERM...(Today and tonight)
Issued at 330 AM CDT Sat Oct 1 2016
Main question for the short term is what will happen with cloud
cover. Closed low over the mid Ohio River Valley will drift north
across Indiana today. Cloud cover associated with this has spread
out across southern MN. Over central MN, we have again seen low
stratus drop down from the Lake Superior region. The going thought
to this point has been that cloud cover from the upper low to our
east would keep a rather steady supply of stratus going for us, but
the HRRR has been showing much of the area going mostly clear by the
afternoon. This may be a little too optimistic, though the GFS and
NAM show clearing skies/drier air working southwest out of northern
WI, so seeing a bit more sun then originally thought, especially for
eastern MN/western WI is looking more likely. Beside that, water
vapor imagery is showing drier air over the MPX area as we sit in an
upper convergence zone and subsidence between the closed low over IN
and a sheared out trough over the Dakotas.
One thing we did remove were the precip chances in the east for
today. Rain overnight has been confined to east of I-39 in central
WI and with the subsidence overhead, it`s hard to envision that
precip making too much farther west today. CAMs and deterministic
models alike keep the MPX area dry today, so didn`t take much
convincing to remove what little pops we had. The main issue for
today is the lack of forcing, with vorticity associated with the IN
low remaining well off to our east.
For temperatures, the key will be the cloud cover. We have a similar
airmass to yesterday in terms of 925-850 temps and as we saw, mix in
a little sun and temperatures have no problem warming into the 70s.
With the thought that we may see more sun than originally thought,
did nudge up highs a couple of degrees. The cloud impacts will
continue into tonight, with a surface ridge axis still expected to
be extending down from Lake Superior. If skies are clear like the
HRRR thinks they will be, it will be a chilly evening, with lows
down in the 40s north of I-94. Beside the cooler temps, if skies are
clear tonight, dense fog will likely become an issue.
.LONG TERM...(Sunday through Friday)
Issued at 330 AM CDT Sat Oct 1 2016
The focus in the long term is a weather system moving through in
the Tuesday through Thursday timeframe. Prior to that, some fine
early fall weather will occur Sunday and Monday as low level
ridging slowly weakens across the Upper Mississippi Valley. We may
have to contend with some fog once again Sunday morning, but this
will depend on how much wrap around cloud cover still exists from
the upper low to our east.
The mid week weather system is a powerful upper level low pressure
system driving through the western half of the country by
Wednesday. The onset of the showers into western MN for late
Monday night and early Tuesday is in good agreement between the
GFS/EC and Canadian. However, the GFS and Canadian drive much of
the system through our FA from Tuesday through Wednesday while
the EC is more Wednesday into early Thursday. This delay in the EC
is tied to a secondary upper trough pushing across the central
plains which the other two solutions don`t have.
All three solutions are pretty adamant on rainfall totals being
around an inch. This seems plausible given we are in the right
entrance region of the upper jet, strong moisture transport occurs
with 925-850mb layer winds around 45 knots, surface dew points
reaching near 60 with 850mb dew points near 50 degrees. In
addition, the PWAT forecast from the GFS is near 1.5 inches, which
is a daily max from our sounding climatology for early October.
The GEFS plumes for KMSP are highly concentrated in the 1 to 1.5
inch range with one member over 2 inches.
The area of concern for the heaviest rain right now is south
central MN into west central WI, certainly an area that has been
quite wet lately. This is where the low level frontogenesis is the
strongest as well as the location of the best differential layer
divergence. We`ll be working on the timing over the next few days.
For now, likely pops are indicated for far western MN on Tuesday,
across much of MN Tuesday night and over western WI on Wednesday.
This progression from west to east would be a little fast if the
EC ends up being more correct. The long term then ends with
surface ridging building in.
Temperatures from Sunday through Tuesday will be some 5 to nearly
10 degrees above seasonal normals with readings a few degrees either
side of 70. After the frontal passage with the low pressure system
around midweek, temperatures will be headed down with highs mainly
in the 50s for Thursday and Friday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1055 PM CDT Fri Sep 30 2016
Clouds are on the increase this evening. Similar to last night,
low (IFR) clouds from Lake Superior are dropping southwest across
the area and at the same time 4000-5000ft ceilings are advancing
across the area from the east. Low ceilings with some vis
restriction is expected by the early morning hours at all the TAF
sites. MVFR conditions appear likely with IFR possible.
KMSP...
Initially, a 4000-5000ft deck will move into early tonight, with
lowering clouds bases early tomorrow morning. Ceilings below
1700ft are possible for a couple hours in the morning.
/OUTLOOK FOR KMSP/
Sun...VFR. Wind NE at 5 kts.
Mon...VFR. Wind SE at 5-10 kts
Tue...chance mvfr -trw. SE at 10-15 kts.
&&
.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...RAH
AVIATION...CLF
AREA FORECAST DISCUSSION
National Weather Service Topeka KS
315 AM CDT SAT OCT 1 2016
.SHORT TERM...(Today and tonight)
Issued at 315 AM CDT Sat Oct 1 2016
Main questions through tonight are cloud and fog trends. Upper low
in the Ohio Valley has moved little in recent hours and taking a
more north-northeast turn per water vapor imagery. Cirrus has been
more prevalent than anticipated with RAP 1.5 PV analysis indicating
a weak disturbance moving east across western Kansas likely one
factor for this cloud. Stratus was nearing the northeastern corner
of the state from the east though with the high cloud being somewhat
persistent, there is little evidence of anything more than patchy
and shallow ground fog so far this morning. Latest upstream low-
level VAD winds showing winds near the surface backing from
northeast to north.
Pattern changes little today and tonight with very weak low level
flow and Ohio Valley system nudging northeast. Stratus may push into
northeastern areas early this morning, and increased moisture will
liekly lead to a diurnal cumulus field here in the late morning and
afternoon, but anticipate slow clearing of the cirrus as the PV
anomaly pushes on southeast across the state. As for fog, will opt
to keep a patchy mention nearer the deeper moisture and less
persistent cirrus this morning, but a widespread dense event is
becoming increasingly unlikely. Could see some of the lower cumulus
linger into the evening and am not confident enough in fog for
inclusion tonight as the airmass continues to modify. Weak
isentropic upglide around 700mb/305K ensues late tonight in central
Kansas but very limited moisture quality as this level should keep
any measurable precip in check. Have highs for all but northeastern
areas a bit warmer but cloud trends will of course need to be
watched watched. Lows tonight should again in the upper 40s to lower
50s.
.LONG TERM...(Sunday through Friday)
Issued at 315 AM CDT Sat Oct 1 2016
Sunday a mid and upper level ridge will build across the Plains as
an upper level trough moves off the Eastern Pacific and into the
western CONUS and the upper level low in the Ohio Valley moves
eastward. Soundings show mixing down from around 850 mb on Sunday
yielding highs in the mid and upper 70s. Negative tilt upper trough
rotates out into the Northern Plains Monday and Tuesday. Southerly
flow will bring moisture northward into the Plains ahead of the
upper trough. Forcing will increase across the Central Plains late
Monday and Tuesday as the as the main upper trough translates
eastward. Showers and thunderstorms are possible Monday night mainly
in north central Kansas then across the rest of the area Tuesday
through Wednesday. Shear and instability will be sufficient for a
few strong to severe storms Tuesday evening in western and central
Kansas and on Wednesday ahead of the cold front. Upper level jet
will provide additional lift with northeast Kansas in the right
entrance region on Wednesday. Morning convection will play a role in
later development across the area both days. The upper trough axis
looks to move east of the cwa by early Thursday which should bring
an end to the precipitation. The GFS and ECMWF differ with timing
and the GFS brings additional energy across Kansas on Thursday which
may linger precipitation through the morning hours or into the
afternoon. A frontal boundary will move through on Wednesday and
will usher in cooler air for the last half of the week. Highs
generally around 80 on Monday will cool off back into the lower 70s
for the end of the week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1143 PM CDT Fri Sep 30 2016
Prospects for dense fog continue to diminish as cirrus has
overspread the forecast area and nearly calm surface winds make
any moisture advection negligible. So have continue to back off on
VSBY restrictions at TOP and FOE. Stratus over northern MO is
progged by the NAM and GFS to remain mainly east of the MO river
and the RAP appears to initialize the clouds to far west. So in
general think a VFR forecast is likely to persist. Have kept a
tempo for some MVFR VSBY around sunrise in case a break in the
cirrus allows enough radiational cooling for some ground fog.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...53
AVIATION...Wolters
Area Forecast Discussion
National Weather Service Bismarck ND
925 AM CDT Sat Oct 1 2016
.UPDATE...
Issued at 918 AM CDT Sat Oct 1 2016
Quiet Saturday expected across western and central ND. Lingering
showers have exited the north central and scattered clouds will
remain over the James River Valley this morning. Otherwise sunny
conditions expected today. Updated latest sensible weather
elements and blended to late morning temperatures.
UPDATE
Issued at 624 AM CDT Sat Oct 1 2016
We are void of any decent radar returns so will maintain a dry
forecast after 12Z this morning. All other forecast elements
remain on track for this product issuance.
&&
.SHORT TERM...(Today and tonight)
Issued at 355 AM CDT Sat Oct 1 2016
Warm, above-normal temperatures and plenty of sunshine will greet
western and central ND for the first day of October today.
As of 08 UTC, a few light showers continue over east central ND in
association with a modest shortwave trough and related vorticity
maximum. Overnight rapid-refresh guidance (the RAP and HRRR) has
been accurately assimilating observed radar trends and has been
rather steadfast in calling for the showers to diminish by 12 UTC
as the vorticity maximum shears northeastward. That expectation is
supported by recent satellite imagery, which shows both deep-layer
drying and resultant clearing advancing east across the Highway 83
corridor at this hour.
In the wake of the early-day shortwave trough, flow aloft will be
rather lackluster between the 500-mb low drifting around the Great
Lakes region and a deepening trough approaching the northwest U.S.
coastline. The result will be a sunny afternoon, and model-derived
soundings from both coarser-scale guidance like the 00 UTC GFS and
NAM and higher-resolution simulations like the HRRR that have more
sophisticated boundary layer parameterization schemes all support
rather uniform mixing to about 850 mb this afternoon. Despite weak
flow aloft, mixing to that level in the face of seasonably strong
diabatic heating supports highs on the warmer side of the guidance
envelope today, especially since soils and vegetation are drying.
We are thus calling for highs well into the 70s F, with lower 80s
F expected in parts of western ND. Southerly winds in the boundary
layer are forecast to peak between 15 and 20 kt, lower than in the
last few days, so while there will be a bit of a breeze, it won`t
be windy by any means.
Tonight, a weak shortwave trough that is forecast to generate some
convection in central MT this afternoon and evening will approach
western ND. However, we maintained a dry forecast area-wide since
the 00 UTC multi-model consensus didn`t provide much support for
the remnants of that activity reaching the state before daybreak.
Lows will be mild for this time of the year, mainly in the lower
50s F.
.LONG TERM...(Sunday through Friday)
Issued at 355 AM CDT Sat Oct 1 2016
The focus of the long term forecast is on potential impacts from a
powerful upper-level trough and accompanying strong surface low
which is expected to cross the region next week. However, based on
recent trends in deterministic and ensemble guidance, it appears
that the heaviest precipitation with this system may end up being
west of the area, across MT.
Mid-level lapse rates are forecast to gradually steepen Sunday and
Sunday night, which will yield an uptick in instability and thus a
chance of showers and thunderstorms is in place as the flow aloft
takes on a more definitive southwest trajectory. However, taken at
face value, the 00 UTC GFS, NAM, and ECMWF suggest that the chance
of convection will be minimized by 1) an early-day timing of the
weak shortwave trough Sunday, before diurnal instability has had
an opportunity to increase, and 2) increasing amounts of MLCIN for
elevated parcels on Sunday night.
A greater chance of precipitation, including the risk of strong to
isolated severe thunderstorms, is expected Monday and Monday night
when strong height falls occur aloft as a 500-mb low reaches south
central MT. Boundary layer dewpoints in the middle to upper 50s F
as forecast by the normally-well-verifying 00 UTC NAM would yield
afternoon and early evening MLCAPE of 500-1200 J/kg and increasing
southerly flow aloft will yield 0-6-km bulk wind shear of 40-50 kt
by early evening, especially in southwestern ND. This may produce
organized storms, and indeed most NAM soundings are analogs to at
least marginal severe storm environments even though the flow is
forecast to lack much directional shear above 1 km.
Thereafter, the 00 UTC GFS and its ensemble members made a strong
move in the direction of the 12 and 00 UTC ECMWF in calling for
the 500-mb low to lift from eastern MT into southern Saskatchewan
with a prominent dry slot across most of western and central ND on
Tuesday and Wednesday. We stayed the course with the multi-model
consensus for our precipitation forecast, maintaining chance-type
PoPs in that period since the trough is still offshore and thus
its track is far from set in stone. Having said that, the 00 UTC
GFS ensemble made a dramatic shift toward a drier scenario across
western and central ND. For example, only one of its members has
more than one-half inch of QPF at Bismarck whereas the 12 UTC GFS
ensemble had a mean QPF of almost an inch. While the GFS ensemble
tends to be under-dispersive, this signal is certainly noteworthy.
If this trend continues, it`s possible the biggest impact with
this system may actually be the cold air advection in its wake,
which could yield a freeze by Thursday night/Friday morning if
the 00 UTC GFS and its MOS-based output is correct.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 918 AM CDT Sat Oct 1 2016
VFR conditions are expected at all TAF sites for the 12Z period.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...CJS
LONG TERM...CJS
AVIATION...TWH
Area Forecast Discussion...Updated
National Weather Service Billings MT
933 AM MDT Sat Oct 1 2016
.UPDATE...
Cold front had pushed through NW MT as of 15Z and was moving a
little faster E than models had predicted. Precipitation was
moving E faster per radar obs than what was depicted in models
including the HRRR/NSSL WRF. Thus have sped up the onset of
precipitation to 15-18z in the W and spread it E faster than what
was shown in previous forecast. SREF instability and shear
parameters and SPC indicated a marginal severe threat over the far
NW zones late today for winds and hail. Right-rear quadrant of jet
will help enhance this possibility. Have emphasized the
thunderstorm threat a bit more for this area through 03Z. Also
lowered dewpoints a couple of degrees for the afternoon based on
RAP soundings. Increased sky cover faster per the above. Arthur
&&
.SHORT TERM...valid for Tdy and Sun...
Water Vapor imagery shows a strong ridge over the high plains
with an upstream trof off the Pacific coast, all of which is
evolving slowly courtesy of blocking over the eastern CONUS
including an Ohio Valley low. There is a small area of
showers/t-storms moving into south central MT in RRQ divergent
region which should stay west of our cwa over the next few hours.
Looking further upstream, a shortwave is seen in northern
California which will lift thru the northern great basin toward
central MT today. This energy and a cold frontal passage will
bring a west-to-east moving band of showers and t-storms late this
afternoon and tonight. Convection should begin in our west around
20-21z with sbcapes up to 500 j/kg. Main risk could be some
enhanced wind gusts near places like Livingston, Big Timber and
Harlowton during the late afternoon. For Billings, best
opportunity for a shower or t-storm looks to be between 6-9pm.
Activity will shift east thru the night and early Sunday as a more
stable and cooler surface ridge slides in from the west.
Winds will shift to easterly on Sunday per the building lee side
surface ridge. As Pacific low begins to move inland, we will see
a quick transition to southerly isentropic ascent and the next
chance of showers especially over southern/western areas on
Sunday. As upper low moves through the great basin the southerly
flow aloft will become much more diffluent, with moisture
advection and increasing instability. Have raised pops to likely
across much of the cwa Sunday night, with potential for some
embedded t-storms thru the night per the ascent and showalter
indices near -1C or -2C. An interesting night of weather for sure.
Today will be the final warm day with high temps into the 80s
across much of the cwa. Post-frontal cooling will bring highs down
to the 60s and lower 70s, warmest in the east, on Sunday.
JKL
.LONG TERM...valid for Mon...Tue...Wed...Thu...Fri...
The aforementioned Pacific low and associated trough will move
into the Great Basin area on Monday, providing a diffluent flow
aloft across southern Montana and northern Wyoming.
The track of the aforementioned low and location of the
precipitation still remains somewhat uncertain, although models
have now started to converge on more of a westerly track than
previous runs. This would lift the low into southern Montana
Monday night, moving into northeast Montana Tuesday/Tuesday night,
and eventually into North Dakota and southern Canada on Wednesday.
Moisture, energy, and instability advecting over the region will
bring periods of showers and thunderstorms to the area on Monday.
Best precipitation chances will be across central and western
areas as a surface low and dry slot is progged to move into
southeast Montana. Snow levels will begin to fall Monday
afternoon allowing for high elevation snow. Periods of showers
will continue into Tuesday as the low lifts through the region
allowing for wrap- around precipitation to affect the area. Again,
best precipitation chances across central and western areas. Shower
activity will begin to decrease on Wednesday as the low lifts off
to the north and east. As the low lifts off to the north and
east, the pressure gradient will tighten over the area allowing
for strong northwest surface winds to form, mainly across central
and eastern areas. Showers remain possible across the west
Wednesday afternoon as a weak disturbance moves through northwest
flow aloft. Shortwave ridging then looks to build in over the
Northern Rockies for Thursday and Friday bringing generally drier
conditions. Another disturbance is then progged to move into the
region on Saturday bringing more shower chances.
High temperatures across the planes on Monday are expected to be
in the 50s west, with the 60s and low 70s east. Highs on Tuesday
will range from the 40s to low 50s, with high temperatures mainly
in the 50s expected through the rest of the week.
Given the uncertainty in the system that still remains for the
first half of the week, it is hard to nail down precipitation
amounts at this point. As we get closer in time, we should have a
better idea. STP
&&
.AVIATION...
Middle to high level clouds will begin to increase from the west
today as a front approaches the region. As the cold front crosses
the area during the afternoon and evening, winds will shift out of
the west. Scattered showers and thunderstorms will first affect
areas west of KBIL this morning into the afternoon, then will
expand eastward to near KBIL for this evening. VFR will prevail,
although MVFR is possible near the stronger showers/storms.
Mountains could be obscured at times in showers/storms. RMS/Arthur
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Sun Mon Tue Wed Thu Fri
-------------------------------------------------------
BIL 082 052/067 052/057 042/049 040/053 040/054 041/059
2/T 42/W 67/T 87/W 33/W 22/W 11/B
LVM 078 043/062 046/055 039/047 036/050 035/052 037/056
4/T 34/T 67/T 75/W 33/W 32/W 12/W
HDN 083 050/070 050/062 041/048 040/052 038/054 040/059
0/U 31/B 56/T 77/W 43/W 22/W 11/B
MLS 084 056/072 055/070 045/049 038/050 036/052 037/059
0/U 32/W 65/T 68/W 53/W 22/W 11/B
4BQ 083 054/072 054/074 043/050 037/051 035/054 037/061
0/U 22/W 54/T 54/W 33/W 22/W 11/B
BHK 080 052/072 052/072 044/050 037/049 033/050 035/056
0/U 23/W 56/T 65/W 43/W 22/W 11/B
SHR 084 051/069 049/065 042/050 037/052 036/053 037/060
0/U 22/T 45/T 65/W 32/W 22/W 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
720 AM CDT SAT OCT 1 2016
.UPDATE...
Issued at 720 AM CDT Sat Oct 1 2016
Please see the updated 12Z Aviation Discussion below...
&&
.SHORT TERM...(Today through Sunday)
Issued at 419 AM CDT Sat Oct 1 2016
The cut off upper low over the Lower Ohio river valley early this
morning, along with a weak ridge axis extending over northern
Minnesota will remain in control of weather for the Northland
through the weekend. The upper low will gradually move north across
Indiana today, then slowly ease northeast into far southeast Ontario
by Sunday afternoon. This low is going to do little more than
bring some mid and high clouds to the eastern sections of the
forecast area through Sunday, with some small rain chances for
Price county. Stratus that has developed over the area downstream
of Lake Superior the last few mornings is here once again, with
the relatively warmer -mid 50s- lake modifying the airmass that is
in the mid 40s where the clouds are clear. Expect this behavior
once again tonight, with stratus developing over the head of the
lake and over the Bayfield Peninsula in the lee of the light east
to northeast flow over the lake. The signal is not as strong as it
was the last two nights, but the pattern is about the same, and
there really hasn`t been significant change in the airmass, so it
seems best to assume the stratus will form again. The similar
airmass and only small changes in cloud cover should favor a
persistence forecast in temperatures, with highs both days getting
into the middle and upper 60s and upper 50s/low 60s near the lake.
Onshore flow is weaker on Sunday so it should be a little warmer
near the lake then. Lows to be very similar as well, dipping into
the low 40s where it clears out, with mid and upper 40s under the
cloud cover.
.LONG TERM...(Sunday night through Friday)
Issued at 419 AM CDT Sat Oct 1 2016
Sunday evening continues the long-awaited departure of the
stagnant cut-off low. By 03.00Z, that feature is forecast to be
over the eastern Great Lakes and progressing eastward with time.
Farther to the west, a high pressure ridge will be positioned over
the Plains and the Upper Midwest. A weak shortwave trough is
forecast to move across the northern Canadian Prairie Provinces
overnight and early Monday. Surface high pressure over the western
Great Lakes, with the transient low to the north, will continue
the development of a southerly return flow across the region
Sunday night into Monday.
The upper-level ridge will advance eastward ahead of a deepening
longwave trough digging across the western United States by Monday
night. A cold front will push across the Dakotas and into western
Minnesota overnight with increasing cloud cover and rain showers
spreading east toward the Northland. Tuesday afternoon through
Wednesday evening appear quite soggy with and area of rain, and a
few embedded thunderstorms, slowly moving eastward ahead of the
decelerating cool front. Twenty-four hour rainfall of 1 to 2
inches seems likely for the eastern two-thirds of my CWA.
Differences in the deterministic and ensemble guidance increase
after Wednesday. The variety of solutions for the track and
intensity of Hurricane Matthew, and the resultant quasi-Rex Block,
produce a wide spread of sensible weather for the area. The
deterministic GFS brings the closed upper low slowly northeastward
into southern Manitoba by Thursday morning with most of the GEFS
members farther west. The ECMWF and GEM both feature a more
progressive solution with the ECMWF opening the low back into a
trough. Prefer the slower GFS solution and nudged the consensus in
that direction.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 720 AM CDT Sat Oct 1 2016
Low stratus and fog developed over western Lake Superior and
drifted across northwest Wisconsin and northeast Minnesota
overnight. The HRRR and RAP models have been doing a good job
handling the low-level moisture overnight and yesterday, so have
trended the ceilings and visibilities similar to that guidance.
Expect the low stratus and fog to lift gradually this morning,
with visibilities improving first, followed by ceilings.
VLIFR/IFR categories are expected early today, improving to VFR
for all sites by late morning/early afternoon. Light winds and
little cloud cover should be conducive for MVFR fog once again
tonight. DLH is the notable exception to this trend, with fog and
low stratus forecast to develop over the lake and move inland
after 02.03Z. Confidence for this forecast package is average.
Visibilities and ceilings may lift faster than currently forecast
this morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 63 45 65 46 / 10 0 0 0
INL 66 49 69 48 / 0 0 0 0
BRD 68 46 69 49 / 0 0 0 0
HYR 69 44 67 44 / 0 0 0 0
ASX 62 47 64 44 / 0 0 0 10
&&
.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...Huyck
SHORT TERM...LE
LONG TERM...Huyck
AVIATION...Huyck
Area Forecast Discussion
National Weather Service Grand Rapids MI
945 AM EDT SAT OCT 1 2016
LATEST UPDATE...
Update/Marine
.SYNOPSIS...
Issued at 311 AM EDT Sat Oct 1 2016
Low pressure will slowly spin across Lower Michigan bringing
occasional rain showers through the weekend. Fair weather will
arrive early next week as the low finally moves away.
&&
.UPDATE...
Issued at 945 AM EDT Sat Oct 1 2016
I updated the zones/grids to put significantly more detail in
where and when it would be raining. The HRRR and RAP model
continue, run after run to show the band of showers moving
westward across our now western CWA. That will move off shore by
noon. The area of broken clouds over northern Indiana will rotate
northward into our southern CWA (as the entire system continues to
drift northward) bringing more instability to area near and south
of I-96 by early afternoon. As a result I put isolated
thunderstorms back in the forecast for late morning into early
evening. Since a little sunshine would result in the instability
being surface based, cold air funnels are not out of the question
with these storms. I do not see another concentrate band of
showers crossing our CWA this afternoon or this evening but
scattered showers and isolated thunderstorms should be expected.
&&
.SHORT TERM...(Today through Monday)
Issued at 311 AM EDT Sat Oct 1 2016
Current radar loop looks remarkably similar to the past two
nights, with rain showers still streaming in from the southeast
into the SE forecast area as the upper cutoff low spins across
the Ohio Valley. It is slowly moving back north into Lower
Michigan before finally getting kicked east as longwave trough
moves into the western CONUS early next week.
Expect rain showers to continue into tonight and Sunday before
tapering off Sunday night as the occluded low moves out of the
forecast area. Marginally steep lapse rates this afternoon makes
diurnal enhancement of thunderstorms possible. We are seeing
cellular convection forming on radar south of the Ohio and Indiana
border already and expect this to move north today.
.LONG TERM...(Monday night through Friday)
Issued at 311 AM EDT Sat Oct 1 2016
Sfc/upper level ridging will bring fair and mild weather Monday night
through Wednesday. Temperatures will undergo a gradual moderating
trend early to mid next week as flow becomes southerly and the upper
level ridge builds in. High temperatures will reach the lower 70s
by Tuesday and will reach well into the 70s by Wednesday.
The next chance for showers will come Wednesday night through late
in the week as a sfc and upper level low pressure system moves slowly
northeast across the upper midwest. This system will pull a
stronger cold front through our area very late next week with
potential for a significantly cooler airmass to move in for next
weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 737 AM EDT Sat Oct 1 2016
IFR ceilings and visbys will be widespresend today as showers and
a few thunderstormsa are expected. The rain will continue into
tonight.
&&
.MARINE...
Issued at 945 AM EDT Sat Oct 1 2016
I have added water spouts back into our near shore forecast since
with the upper low drifting northward the instability will do the
same. Given the water is warmer than the air and the low to mid
level winds have decreased below 20 knots below 500 mb, any
convective elements developing or moving over the Near Shore could
result in water spouts development. Due to the northeast winds
and water spouts that do develop would move away from shore.
&&
.HYDROLOGY...
Issued at 1109 AM EDT Fri Sep 30 2016
The Sycamore Creek is nearing its crest over a foot above
bankfull, and will begin its slow recession which may modulated
by any additional rainfall Friday into Saturday. Other rivers
approaching bankfull the next few days include the Red Cedar above
Williamston, the Looking Glass near Eagle, and the Grand at Ionia.
The current forecasts are dependent on roughly another 0.75 inches
falling in those basins through Saturday morning. Will hold off
on flood advisories for those rivers until confidence is higher.
&&
.GRR Watches/Warnings/Advisories...
MI...None.
LM...None.
&&
$$
UPDATE...WDM
SYNOPSIS...Ostuno
SHORT TERM...Ostuno
LONG TERM...Laurens
AVIATION...Ostuno
HYDROLOGY...CAS
MARINE...WDM
Area Forecast Discussion
National Weather Service Wilmington OH
1048 AM EDT Sat Oct 1 2016
.SYNOPSIS...
A large upper level low will drift slowly north through the Great
Lakes this weekend. Under the influence of this upper low expect
cool temperatures and a chance for rain today and Sunday. A
warmer and drier airmass will build into the region through the
middle part of next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Upper level low can be seen on radar this morning with the center
located just northwest of Mercer county. Latest 1.12Z KILN
forecast sounding showed PWATs around 0.8" with lapse rates
continuing to come down and the low slowly moves away. The HRRR/
RAP/ and WRF-DART don`t show to much coverage today while the
NMM/ ARW and NCEP WRF show slightly more robust coverage. This
afternoon GFS and RAP forecast soundings show ML Cape values only
around 300 J/kg. Looking at 500 mb also reveals most of the lift
heading north with the low. There is a secondary band of weak PVA
that moves just south of the area this afternoon which does have
some reflection on the RAP omega field. The NAM shows more potent
lift across our eastern zones. Given the data have trended PoPs
down to account for lift being weak.
Prev Discussion->
Upper level low evident on water vapor imagery centered over
southeast Indiana this morning. Model solns generally similar with
this upper low drifting a little north toward the Indiana/ Michigan
border by evening. Best lift/moisture to lift north out of ILN/s fa
around the periphery of this upper low. Weak forcing in the form of
low level convergence rotates around this low into ILN/s fa this
afternoon. Therefore, will continue likely pops over the western
counties. With marginal instability will continue to limit thunder
chances to slight chance. Temperatures will continue to be cool
with highs ranging from mid/upper 60s west under the low to around
70 east.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
With the upper low track ene across southern lower Michigan, rain
chances will diminish tonight. lows look close to normal and
generally in the lower and middle 50s.
As the low drifts ene into srn Ontario Sunday expect to see more
in the way of sunshine. In the broad cyclonic flow around the
periphery of this low can not rule out afternoon showers. The best
threat for showers will occur across the ne counties. Expect highs
on Sunday to range from the upper 60s north to the lower 70s
south.
The upper low finally loses it`s grip on the region and surface
high pressure builds in from the west. Expect dry conditions with
temperatures near normal Monday. Highs to range from around 70
north to the lower/middle 70s south.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The long term will open up with a closed low ejecting off to the
east over New England with weak mid level ridging building into
the region. The latest 30.12Z CMC, GFS, and ECMWF have come into
pretty good agreement with the timing of the low pushing off the
coast and away from the CWA. As the weak ridging forms over the
area another upper level system will be pushing into the Mountain
West which will push the next cold front into the area Friday.
Model discrepancy continues to be an issue for the second part of
the next work week though. The 30.12Z ECMWF and CMC both try to
linger some of the energy from the upper level low over New
England under weak ridging. This in turn helps to block
progression of Matthew and push the cold front through the area
slightly quicker.
Regarding more of the details, a general warming trend is expected
to commence starting Tuesday thanks to mid level ridging and a
warming low level thermal profile. 850 mb temperatures Monday are
forecasted to be around 9 degrees C and warm towards 13 degrees C by
Wednesday. This would support high temperatures in the upper 70s to
around 80 degrees, or about 10 degrees above normal for this time of
year. PWATs also fall below 1.00" so am expecting dry weather Monday
through Wednesday.
For the second half of the extended models begin to differ on the
timing of the passage of a surface cold front and the circulation of
Matthew. The ECMWF has a trough axis push through the area Friday
morning supporting a cold front passage Friday morning as well. The
GFS on the other hand supports the cold front passing through Friday
evening. In general, PWATS (~1.2") and upper level lift appear to be
sufficient for showers and thunderstorms with the frontal passage
but given low confidence in timing have kept PoPs in the chance
category for now. Have also kept grids reflecting more of the ECMWF
and CMC solution.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Slow moving upper low centered near the OH/IN border will
continue to affect TAF sites. IFR ceilings have formed at
CVG, with BR reducing visibilities to MVFR at ILN and LCK.
Expect conditions to improve during daylight hours. However,
showers are forecast to develop by afternoon, and a few
thunderstorms may occur this afternoon in the vicinity of DAY, CVG
and LUK as instability increases. Showers should diminish by 00z
Sunday under decreasing instability and forcing as the upper low
lifts north to Michigan. BR may form again late in the forecast
period. Winds are forecast to stay under 10 knots out of the
south. West winds and VCSH are forecast for CVG after 12z Sunday.
OUTLOOK...IFR ceilings possible Sunday near 12z.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Haines/AR
NEAR TERM...Haines/AR
SHORT TERM...AR
LONG TERM...Haines
AVIATION...Coniglio
Area Forecast Discussion
National Weather Service Lincoln IL
1013 AM CDT SAT OCT 1 2016
.UPDATE...
Issued at 1013 AM CDT Sat Oct 1 2016
Upper low has reached northeast Indiana late this morning, with
lobes of energy rotating around the northwest flank of the low.
Decent area of showers extends from near Milwaukee southward to
Danville as of 10 am, but areas further west mostly dry with some
light showers or drizzle from Galesburg to Springfield. Main focus
into the afternoon will remain over the northeast CWA as the waves
of energy get some enhancement off the lake. Have updated the PoP
trends to concentrate the highest chances from around
Bloomington-Danville with mainly scattered showers elsewhere.
Little change needed to temperatures at this time.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 324 AM CDT Sat Oct 1 2016
Short term will still be dominated by the slow moving low pressure
system just east of Illinois. The upper low center is expected to
gradually lift north through eastern Indiana today, while the
surface low center generally remains in western Indiana along the
Illinois border. Various lobes of energy are depicted to rotate
around the upper low through the day, with plenty of low level
moisture available to produce periodic rain showers and drizzle.
Low clouds, fog and drizzle will start the day, with periods of
heavier drizzle or showers at times the rest of the day. While the
better chances appear to reside in eastern Illinois, showers look
to hold together into western Illinois per the latest HRRR and RAP
model updates. Rainfall amounts should generally remain less than
a quarter inch, with most locations around a tenth of an inch. The
potential for thunder looks low, but a few rumbles of thunder
could develop this afternoon east of I-57. Diurnal temperature
swings will be held in check by the overcast skies, as high temps
only climb 10 to 12 degrees above morning lows. Highs should reach
the upper 60s to around 70 today.
Tonight, showers and drizzle should dissipate overnight, as the
surface and upper lows pull farther away to the northeast. Stratus
clouds will likely linger through at least Sunday morning. Patchy
fog will be possible as well, due to plenty of boundary layer
moisture. Low temperatures will be in the middle 50s.
.LONG TERM...(Sunday through Friday)
ISSUED AT 324 AM CDT Sat Oct 1 2016
Large 564 dm 500 mb low over southeast Indiana will lift up
toward Detroit by sunrise Sunday, and into nw NY by dawn Monday.
IL will still be in a cyclonic flow on Sunday, as upper level low
pulls way from the region, though chances of rain showers to lift
ne of CWA on Sunday. Mostly cloudy skies expected most of the day
Sunday, though skies could become partly sunny during Sunday
afternoon especially sw of I-74 as nw winds bring in some drier
air. Highs around 70F from I-74 northeast and in the lower 70s sw
of I-74 on Sunday. Partly cloudy skies Sunday night with lows in
the low to mid 50s as weak surface high pressure ridge settles in.
Upper level ridge moves into the Great Lakes region on Monday and
provides a nice day to central/southeast IL with partly to mostly
sunny skies, light winds and seasonable highs in the low to mid 70s.
Fair skies Monday night with lows in the mid 50s. Upper level ridge
shifts east into New England on Tuesday, while cutoff upper level
low off the Pacific nw coast tracks into the northern high plains.
Another nice early fall day expected for IL with mostly sunny skies
on Tue and southeast winds bringing milder highs in the upper 70s.
Dry conditions expected to continue through Tue night with lows in
the upper 50s to around 60F.
00Z models still differ with movement of cold front eastward across
IL around Thursday. ECMWF model is keep CWA dry yet on Wed, while
GEM brings qpf into the IL river valley and GFS has qpf as far east
as I-55. Category 5 Hurricane Matthew with winds of 160 mph at 13.3N
and 72.5W is forecast to track northward into the Bahamas during Wed
and this may tend to slow the upper level trof and cold front west
of IL then. Have dry conditions over IL on Wed and 20-40% of showers
and thunderstorms by Wed afternoon from I-55 west with highest pops
of 30-40% nw of IL river. Highs in the upper 70s west of the IL
river on Wed with lower 80s east of the IL river. Have increasing
pops from west to east during Wed night with approaching of cold
front, with likely pops over IL river valley. Then this cold front
appears to move over IL on Thu as it weakens somewhat. Continued 40-
50% pops on Thu with highs in the lower 70s over IL river valley and
upper 70s over the Wabash river valley. Temps continue to cool
behind the front on Fri/Sat with highs in upper 60s/lower 70s on Fri
and mid to upper 60s on Sat. Dry conditions expected Fri and
Saturday with surface high pressure moving into from the west.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 637 AM CDT Sat Oct 1 2016
The large upper low over southern Indiana will finally make some
slow progress to the north today. An elongated surface low in
eastern Indiana will bring IFR conditions to the forecast area
this morning, along with drizzle and showers. As the low shifts
north through Indiana, the showers and drizzle threat will hold
over the area thru the afternoon with a typical lifting of the
cigs to MVFR. As the low shifts away from our area tonight, MVFR
cigs are expected to continue, with ceilings dropping to IFR again
after midnight. Plenty of surface moisture will set the stage for
some MVFR fog as well. Surface winds will start out from the N-NE
this morning, then begin to shift around to the NW this afternoon
and evening. Wind speeds will generally remain below 10 kt through
the period, under a weak surface pressure gradient and limited
mixing down of the mid-level winds.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1105 AM EDT Sat Oct 1 2016
.UPDATE...
Issued at 1105 AM EDT SAT OCT 1 2016
14z sfc analysis shows that the center of low pressure has backed
off to the northwest of the area, though relative low pressure
remains over eastern Kentucky. This, and the upper low not far
away, will continue a threat of light pcpn through the area
today, but mainly for the Bluegrass region of Kentucky per the
latest HRRR and NAM12 model guidance. The morning fog has cleared
out so have removed that from the Wx grids and zones. Temperatures
currently in the upper 50s to low 60s will be capped today by the
clouds and sprinkles/showers. Dewpoints are generally in the low
to mid 50s through the area with light and variable winds. This
update included the latest CONSShort and ShortBlend guidance as
well as the current obs and trends. These have been sent to the
NDFD and web servers along with an updated set of zones.
UPDATE Issued at 744 AM EDT SAT OCT 1 2016
Light showers/virga continue to develop across central Kentucky,
but tend to be diminishing in intensity as they move into eastern
Kentucky when farther displaced from forcing aloft. Still possible
to see some of these across the Bluegrass region through the
Interstate 75 corridor later today with diurnal heating.
&&
.SHORT TERM...(Today through Sunday)
Issued at 346 AM EDT SAT OCT 1 2016
Upper low continues to slowly propagate north, now located just
about directly over Cincinnati. This will keep isolated shower
chances confined to the Bluegrass region down toward Lake
Cumberland as upper forcing continues to depart off toward the
lower Great Lakes today. Thunder chances still looking anemic
with surface-based instability of perhaps a couple hundred J/kg
complete with a stout temperature inversion near 700 mb.
Increasing heights/thicknesses and warmer air advecting in on
southwesterly flow will be somewhat offset by increasing cloud
cover rotating into the region this morning and afternoon, keeping
high temperatures in the mid 60s to low 70s.
Weak surface ridging will build north tonight across southeastern
Kentucky, allowing for another appreciable ridge/valley split as
valley temperatures dip into the upper 40s with ridgetops
remaining in the low-mid 50s. Shower chances will continue as
energy skirts around the southern flank of the upper low riding
through the southern Great Lakes. Valley fog will also be in the
offing, especially across southeastern Kentucky where quicker
clearing will take place.
Sunday will offer up one final day of isolated showers, mainly
north of Hal Rogers Parkway/Highway 80 in closer vicinity to any
impulses which may clip eastern Kentucky. Cloud cover will slowly
diminish from south to north through the day with warmer air once
again kicking in aloft, allowing for high temperatures to reach
normal values in the low-mid 70s.
.LONG TERM...(Sunday night through Friday)
Issued at 404 AM EDT SAT OCT 1 2016
Strong upper level low will continue to exit to the northeast during
the extended portion of the forecast. This will leave general
ridging across the Ohio River Valley, with surface high pressure
expected to be in control for Kentucky and points northward from
Monday through midweek. Winds will shift from a northerly direction
to more southerly flow by Tuesday as we find ourselves on the
southwest flank of the center of high pressure. This will allow for
better WAA and temperature modification. While highs on Monday will
stay with in the mid 70s, temperatures by Tuesday will increase to
the upper 70s to around 80 degrees, with a slight uptick in humidity
expected as well. Given the strong southerly pull generated from the
soundings, in addition to good mixing this day, went ahead and
nudged temperatures up a degree or two higher in some locations
compared to the Superblend. Similar conditions will be in place on
Wednesday as well with southerly flow still in place.
Meanwhile, a strong upper level low, which will be located across
the far western conus during the day Monday, will continue on a
northeast track, reaching the Canada/North Dakota border by 0Z
Wednesday. This will result in deep upper level troughing across
much of the western and central conus, and decreasing heights across
the Ohio River Valley. The closed low will lose some momentum and
strength, but should continue to push northeastward through the rest
of the work week, with the axis of the trough moving across Kentucky
Thursday night into Friday (given some slight model discrepancies
this far out in the forecast). At the surface, a low pressure system
will follow in the tracks of the upper level low. It should lag
slightly behind the upper level feature, moving into the northern
Dakotas/Canadian border throughout the day Wednesday. The cold front
produced from this system will extend southward the length of the
conus, and should be located across the central plains and into
Texas by Wednesday afternoon. This will be yet another contributor
to the increasing southerly flow across the Ohio River Valley as
this frontal zone approaches.
The cold front should arrive and traverse the state sometime during
the day Friday (once again this differs slightly given the lack of
forecast agreement this far out). However, continuing to note some
large discrepancies in the extent of precipitation associated with
this frontal passage. As the low continues to pull north while the
front pushes eastward, we stray farther and farther away from the
best forcing. GFS run 24 hours ago showed no precip across the
region as the front passed. However latest 00Z run shows a skinny
but defined line along the frontal axis traversing western KY during
the day Friday, but still loses coverage as it makes it into eastern
KY Friday evening/night. Meanwhile, the ECWMF is much faster and
continues to bring a line of precipitation across the entire state
Thursday night through Friday morning, exiting east of the state by
18z Friday. Which model is right is yet to be discovered, however
given the strong uncertainty, did not feel confident enough to lean
towards one or the other. Kept with the blend, which resulted in
slight chance pops closer to the ECMWF timeline. Given the weakening
boundary and the lack of any instability in the forecast soundings,
chose to remove thunder wording with the precipitation chances.
Temperatures will be on a decline after the frontal passage, with
mid 70s expected for highs on Friday, but only upper 60s on
Saturday.
During the extended portion of the forecast, we also continue to
track Hurricane Matthew as it approaches the southeast Atlantic
Coast. The GFS is much more progressive in its movement toward the
conus, showing Matthew reaching eastern FL by Thursday and then
riding northward along the coastline through Saturday, before
merging into the upper level trough system Sunday. The ECMWF is a
bit slower and keeps the system well off the Atlantic coast. the
ECMWF actually seems a bit more realistic in its timing/velocity of
movement northward through the weekend. But once again, given the
lack of agreement this far out in the forecast, it is yet to be seen
which solution will be closer to the truth. Either way, this system
and its influence on the weather, should remain east of the state
during the extended portion of the forecast.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 744 AM EDT SAT OCT 1 2016
An upper level low continues to meander across the Lower Ohio
Valley. This will lead to bands of clouds through the period and
the threat of isolated showers, although these should remain west
of all TAF sites. Patchy valley fog will mix out within the next
couple of hours, while stratus/MVFR ceilings persist through mid
morning at LOZ/SME and possibly SYM. VFR conditions will return by
mid-late this morning as southwest winds generally increase to
5-10 knots. Winds will diminish this evening as low stratus
potentially develops near the Bluegrass region toward Lake
Cumberland. With the main concentration of this and any visibility
reductions being centered northwest of all TAF sites, have opted
to leave mention out for now.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GUSEMAN
LONG TERM...JMW
AVIATION...GUSEMAN
Area Forecast Discussion
National Weather Service Melbourne FL
921 AM EDT SAT OCT 1 2016
.DISCUSSION...
Current-Tonight...A weak quasi-stationary boundary is depicted
across the I-4 corridor early this morning and is forecast to make
slight movement north of Lake/Volusia counties over the next 24
hours. This, as weak high pressure ridging nudges west back into
ECFL. Water vapor imagery shows drier mid/upper level air northward
from the I-4 corridor. Cape 915MHZ wind profilers show generally
light (5-10 kts) SSW/SW winds from just off of the surface through
around 10.0 kft. The KXMR sounding shows a PWAT of 1.78 inches and a
500mb temp of -7.8C. Noticing local observations coming in with some
lower cloud ceilings (stratus) and patchy morning fog along the I-4
corridor. Suspect this will continue to burn off thru mid to late
morning.
MOS guidance has come in lower than previous days for POPs and the
local HRRR mesoscale model is also a bit shy on afternoon
convection. Deeper moisture continues to reside southward while a
presence of a weak front lies across the north. Given both east/west
coast sea breezes will move inland during the day, suspect enough
parameters in place to keep lower end CHC POPs in the forecast
areawide (30 to 40 percent). It could be a delay for much of
anything to get going this afternoon, especially along the sea
breezes, and perhaps the biggest fireworks will take place later in
the day/evening from larger-scale boundary collisions over the
interior. Temperatures aloft remain cool so a few strong storms will
again be possible, mainly over the interior.
Previous...High temps today in the upper 80s/near 90. A more
persistent onshore flow is expected tonight near the coast as the
atlc ridge builds back in which should keep low temps noticeably
milder in the mid 70s at the coast. In addition, nocturnal storms
over the water will have a better chance to approach the coast so
will keep chance PoPs south of the Cape overnight.
&&
.AVIATION...Some early morning stubborn stratus/patchy fog issues
from KDAB/KEVB/KSFB. Suspect this grunge will burn off thru mid to
late morning. Elsewhere...mainly VFR with winds 10 knots or less.
Best chance for storms will be over the interior this afternoon
mainly MCO southward. Tempo MVFR in aftn/evening convection.
Nocturnal convection may redevelop over the Atlantic waters this
evening/overnight. A more persistent onshore flow may bring some of
this activity toward coastal terminals.
&&
.MARINE...Today/Tonight...A weak frontal boundary exists just north
of our local coastal waters this morning. It is forecast to nudge a
bit more northward over the next 24hrs as weak ridging builds across
the area from the east. Light/variable morning winds will become
onshore by this afternoon thru tonight. Wind speeds generally AOB 10
kts. Current precipitation shield over the southern waters is
forecast to diminish thru the morning. Convective focus this
afternoon primarily over the peninsula. A more persistent E/SE flow
developing tonight which may bring some nocturnal showers/storms to
the east coast from the Atlantic. An increasing fetch will gradually
bump up seas to 3 feet offshore today and 4 feet tonight.
&&
.MLB Watches/Warnings/Advisories...
FL...None.
AM...None.
&&
$$
Sedlock/Volkmer
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
614 AM CDT SAT OCT 1 2016
.SHORT TERM...(Today and tonight)
Issued at 330 AM CDT Sat Oct 1 2016
Main question for the short term is what will happen with cloud
cover. Closed low over the mid Ohio River Valley will drift north
across Indiana today. Cloud cover associated with this has spread
out across southern MN. Over central MN, we have again seen low
stratus drop down from the Lake Superior region. The going thought
to this point has been that cloud cover from the upper low to our
east would keep a rather steady supply of stratus going for us, but
the HRRR has been showing much of the area going mostly clear by the
afternoon. This may be a little too optimistic, though the GFS and
NAM show clearing skies/drier air working southwest out of northern
WI, so seeing a bit more sun then originally thought, especially for
eastern MN/western WI is looking more likely. Beside that, water
vapor imagery is showing drier air over the MPX area as we sit in an
upper convergence zone and subsidence between the closed low over IN
and a sheared out trough over the Dakotas.
One thing we did remove were the precip chances in the east for
today. Rain overnight has been confined to east of I-39 in central
WI and with the subsidence overhead, it`s hard to envision that
precip making too much farther west today. CAMs and deterministic
models alike keep the MPX area dry today, so didn`t take much
convincing to remove what little pops we had. The main issue for
today is the lack of forcing, with vorticity associated with the IN
low remaining well off to our east.
For temperatures, the key will be the cloud cover. We have a similar
airmass to yesterday in terms of 925-850 temps and as we saw, mix in
a little sun and temperatures have no problem warming into the 70s.
With the thought that we may see more sun than originally thought,
did nudge up highs a couple of degrees. The cloud impacts will
continue into tonight, with a surface ridge axis still expected to
be extending down from Lake Superior. If skies are clear like the
HRRR thinks they will be, it will be a chilly evening, with lows
down in the 40s north of I-94. Beside the cooler temps, if skies are
clear tonight, dense fog will likely become an issue.
.LONG TERM...(Sunday through Friday)
Issued at 330 AM CDT Sat Oct 1 2016
The focus in the long term is a weather system moving through in
the Tuesday through Thursday timeframe. Prior to that, some fine
early fall weather will occur Sunday and Monday as low level
ridging slowly weakens across the Upper Mississippi Valley. We may
have to contend with some fog once again Sunday morning, but this
will depend on how much wrap around cloud cover still exists from
the upper low to our east.
The mid week weather system is a powerful upper level low pressure
system driving through the western half of the country by
Wednesday. The onset of the showers into western MN for late
Monday night and early Tuesday is in good agreement between the
GFS/EC and Canadian. However, the GFS and Canadian drive much of
the system through our FA from Tuesday through Wednesday while
the EC is more Wednesday into early Thursday. This delay in the EC
is tied to a secondary upper trough pushing across the central
plains which the other two solutions don`t have.
All three solutions are pretty adamant on rainfall totals being
around an inch. This seems plausible given we are in the right
entrance region of the upper jet, strong moisture transport occurs
with 925-850mb layer winds around 45 knots, surface dew points
reaching near 60 with 850mb dew points near 50 degrees. In
addition, the PWAT forecast from the GFS is near 1.5 inches, which
is a daily max from our sounding climatology for early October.
The GEFS plumes for KMSP are highly concentrated in the 1 to 1.5
inch range with one member over 2 inches.
The area of concern for the heaviest rain right now is south
central MN into west central WI, certainly an area that has been
quite wet lately. This is where the low level frontogenesis is the
strongest as well as the location of the best differential layer
divergence. We`ll be working on the timing over the next few days.
For now, likely pops are indicated for far western MN on Tuesday,
across much of MN Tuesday night and over western WI on Wednesday.
This progression from west to east would be a little fast if the
EC ends up being more correct. The long term then ends with
surface ridging building in.
Temperatures from Sunday through Tuesday will be some 5 to nearly
10 degrees above seasonal normals with readings a few degrees either
side of 70. After the frontal passage with the low pressure system
around midweek, temperatures will be headed down with highs mainly
in the 50s for Thursday and Friday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 614 AM CDT Sat Oct 1 2016
Like 24 hours ago, we are dealing with low stratus and fog coming
out of central MN and expect it to act in a similar way today,
though it will not get as far south as it did yesterday. The HRRR
continues to show skies clearing out today, though forecast
sounding show lots of moisture hanging out in the 8k-10k foot
range. Eventually, the NAM/GFS show even this layer drying out
tonight with clear skies and calm winds taking hold. As a result,
was very aggressive with fog mention for all but MSP Sat night/Sun
morning.
KMSP...Like yesterday, MSP may see a sub 500 foot cig this
morning, though the expansion of the fog out of central MN into
the north metro began later than it did yesterday, so will go with
these clouds staying north this morning. Tonight could be a very
foggy night across the region if we see skies clear out. It would
be a radiational fog, which MSP does not typically deal with,
though that could result in some low cigs for Sunday morning as
well.
/OUTLOOK FOR KMSP/
Sun...VFR. Wind NE at 5 kts.
Mon...VFR. Wind SE at 10G20 kts
Tue...Chc MVFR -TSRA late. SE at 10-15G25 kts.
&&
.MPX Watches/Warnings/Advisories...
WI...None.
MN...None.
&&
$$
SHORT TERM...MPG
LONG TERM...RAH
AVIATION...MPG
...Update to aviation forecast discussion...
.SHORT TERM...(Today and tonight)
Issued at 315 AM CDT Sat Oct 1 2016
Main questions through tonight are cloud and fog trends. Upper low
in the Ohio Valley has moved little in recent hours and taking a
more north-northeast turn per water vapor imagery. Cirrus has been
more prevalent than anticipated with RAP 1.5 PV analysis indicating
a weak disturbance moving east across western Kansas likely one
factor for this cloud. Stratus was nearing the northeastern corner
of the state from the east though with the high cloud being somewhat
persistent, there is little evidence of anything more than patchy
and shallow ground fog so far this morning. Latest upstream low-
level VAD winds showing winds near the surface backing from
northeast to north.
Pattern changes little today and tonight with very weak low level
flow and Ohio Valley system nudging northeast. Stratus may push into
northeastern areas early this morning, and increased moisture will
liekly lead to a diurnal cumulus field here in the late morning and
afternoon, but anticipate slow clearing of the cirrus as the PV
anomaly pushes on southeast across the state. As for fog, will opt
to keep a patchy mention nearer the deeper moisture and less
persistent cirrus this morning, but a widespread dense event is
becoming increasingly unlikely. Could see some of the lower cumulus
linger into the evening and am not confident enough in fog for
inclusion tonight as the airmass continues to modify. Weak
isentropic upglide around 700mb/305K ensues late tonight in central
Kansas but very limited moisture quality as this level should keep
any measurable precip in check. Have highs for all but northeastern
areas a bit warmer but cloud trends will of course need to be
watched watched. Lows tonight should again in the upper 40s to lower
50s.
.LONG TERM...(Sunday through Friday)
Issued at 315 AM CDT Sat Oct 1 2016
Sunday a mid and upper level ridge will build across the Plains as
an upper level trough moves off the Eastern Pacific and into the
western CONUS and the upper level low in the Ohio Valley moves
eastward. Soundings show mixing down from around 850 mb on Sunday
yielding highs in the mid and upper 70s. Negative tilt upper trough
rotates out into the Northern Plains Monday and Tuesday. Southerly
flow will bring moisture northward into the Plains ahead of the
upper trough. Forcing will increase across the Central Plains late
Monday and Tuesday as the as the main upper trough translates
eastward. Showers and thunderstorms are possible Monday night mainly
in north central Kansas then across the rest of the area Tuesday
through Wednesday. Shear and instability will be sufficient for a
few strong to severe storms Tuesday evening in western and central
Kansas and on Wednesday ahead of the cold front. Upper level jet
will provide additional lift with northeast Kansas in the right
entrance region on Wednesday. Morning convection will play a role in
later development across the area both days. The upper trough axis
looks to move east of the cwa by early Thursday which should bring
an end to the precipitation. The GFS and ECMWF differ with timing
and the GFS brings additional energy across Kansas on Thursday which
may linger precipitation through the morning hours or into the
afternoon. A frontal boundary will move through on Wednesday and
will usher in cooler air for the last half of the week. Highs
generally around 80 on Monday will cool off back into the lower 70s
for the end of the week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 640 AM CDT Sat Oct 1 2016
Ground fog becoming consistent enough for inclusion for a few
hours but all sites should be VFR by 15Z. Will need to watch
trends for more potential ground fog after 06Z but there is too
much uncertainty for a mention.
&&
.TOP Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...53
AVIATION...65
Area Forecast Discussion
National Weather Service La Crosse WI
309 PM CDT Sat Oct 1 2016
.SHORT TERM...(This evening through Sunday)
Issued at 309 PM CDT Sat Oct 1 2016
Latest 19z surface analysis indicates low pressure over northern
Indiana. Latest mosaic radar shows scattered light rain showers
across parts of eastern Wisconsin...northern Illinois and northern
Indiana.
Main forecast concerns tonight and Sunday are cloud trends. The
01.12z GFS/NAM/ECMWF are in decent agreement in lifting and
weakening upper level closed/surface low into the eastern Great
Lakes Region tonight into Sunday. This will allow any weak vertical
motion/forcing to be east of the forecast area tonight into Sunday.
The forecast area should remain mainly dry tonight into Sunday. The
01.12z GFS/NAM suggest low level moisture below 850mb to wrap around
the upper level closed low into much of the forecast area tonight.
Expect mostly cloudy skies across much of the forecast area.
Surface/upper level ridge begins to build into the forecast area
Sunday. With subsidence and drier air advecting into the Upper
Midwest and forecast area. Clouds are expected to diminish from
north to south across the forecast area during the day Sunday.
.LONG TERM...(Sunday night through Saturday)
Issued at 309 PM CDT Sat Oct 1 2016
The 01.12z GFS/NAM/ECMWF are in good agreement in slowly moving
upper level closed low into the eastern Great Lakes Region and
building upper level/surface ridge into the Upper Midwest Sunday
night into Monday. This will provide dry weather across the forecast
area. The 01.12z GFS/NAM indicate skies will be mostly clear by 00z
Monday...as surface/upper level ridge builds into the area. The
01.12z GFS/NAM bufkit soundings show inversion developing and deep
layer light winds across the forecast area Sunday night. Expect fog
to form in river valleys...favored areas of central Wisconsin and
possibly across the entire forecast area. At this time...introduced
fog in the river valleys and the favored areas of central Wisconsin.
The 01.12z GFS/NAM/ECMWF continue to show differences in timing and
strength of upper level closed low over the northern
Rockies/northern High Plains Tuesday. The 01.12z GFS slightly
faster/stronger than the NAM/ECMWF with the first impulse ejecting
out of the closed upper level low into the western parts of the
forecast area. The 01.12z GFS/ECMWF/NAM show the better moisture
axis/convergence over the western half of Iowa and Minnesota in
association with the impulse. With this...have reduced precipitation
chances to the western parts of the forecast area Tuesday.
The main focus for Tuesday night into Saturday will be a vigorous
low pressure system ejecting out of the northern Rockies late
Tuesday. The GFS and ECMWF are in fairly good agreement with this
feature, but some timing differences do exist, with the GFS being
more progressive. Enough forcing and moisture should be in place for
at least scattered rain showers along the cold front as it moves
through the region, with the highest rain chances coming during the
day on Wednesday. A few rumbles of thunder can`t be ruled out, but
the 01.00Z ECMWF only places around 300 J/kg of MUCAPE over the
region Wednesday afternoon. Models begin to greatly diverge by 12Z
Friday, with the 01.12Z GFS and 00.01Z ECMWF in nearly opposite
phase with the synoptic pattern over the central CONUS. The Canadian
model is in fair agreement with the ECMWF during this timeframe.
Also, the 01.12Z GFS presents quite a different solution than
previous runs, so this run may be an outlier.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1202 PM CDT Sat Oct 1 2016
The RAP continues to suggest that drier air will gradually
overspread the area from the north as the surface low starts to
move slowly off to the east. Visible satellite imagery shows a
hole in the clouds over northwest Wisconsin into central Minnesota
that will drift over KRST this afternoon and could affect KLSE as
well. Even if the clouds hang on into this evening, with the
surface low moving farther away and the drier air coming in,
ceilings are expected to go up to VFR with the clouds then
scattering out for good Sunday morning. Some potential for fog at
KLSE overnight if the clouds can clear out sooner than expected. A
light wind layer should be in place up through about 3 or 4
thousand feet but the concern is whether saturation will occur at
the surface. Neither the 01.12Z NAM or 01.15Z RAP show saturation
occurring so have opted to not include any fog.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ/MAH
AVIATION...04
Area Forecast Discussion
National Weather Service Binghamton NY
331 PM EDT Sat Oct 1 2016
.SYNOPSIS...
Unsettled weather will continue for the remainder of this weekend
into Monday as a slow moving upper level low dominates our
weather. This low will keep a chance for showers in the forecast
through Monday evening. Drier conditions are expected to return by
the middle of the week as high pressure takes control.
&&
.NEAR TERM /THROUGH SUNDAY/...
Radar imagery shows showers mainly over central and north central
PA early this afternoon associated with a plume of moisture seen
on the water vapor imagery. This moisture was associated with a
short wave that was riding north on the east side of the upper
level low over northern Indiana. These showers will move north for
the rest of this afternoon and affect mainly the central southern
tier of NY, western Finger lakes of NY and Bradford county PA in
the BGM forecast area. So have chance to likely POPs in these
areas for the rest of the afternoon.
For this evening, followed the HRRR which eventually brings this
plume of moisture and associated showers farther east to the I-81
corridor by around 00z-02z and then to the Catskills to upper
Mohawk Valley by 06z. Leaned heavily on the HRRR for hourly POP
timing. Used HRRR, plus blended with neighboring offices. Also
broadened the chances for light precipitation tonight as there
will be patchy drizzle as well with continued low-level south-
southeasterly flow and upsloping. Hence keep overcast skies in
through the night as there is little chance for any significant
breaks in the overcast to form given the present low-level flow
pattern. After 06z see just patchy drizzle or light showers and
have trended down POPs from west to east. Highest chances for
precipitation will be in the Catskills to upper Mohawk Valley late
tonight where there will be the most upslope.
Then for Sunday, low-level winds turn more southwesterly which
should lead to some breaks in the overcast. The upper level low
moves east and reaches the eastern Great Lakes between 21Z and
00Z. This will lead to more showers spreading into the Finger
Lakes late in the day. With the lower clouds breaking up chances
for drizzle will wane Sunday morning.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
3 PM Update...
Good model agreement with an upper level low moving slowly east
across upstate NY Sunday night to Monday night. Showers will
remain across the area into Monday evening. Some diurnal
thunderstorms also possible in the afternoon and evening both days
with some surface heating and cold air aloft. Best chances of
showers and thunderstorms in central NY. Rainfall less than half
an inch for this period. Deeper moisture stays to the southeast of
the cwa.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
3 PM Saturday update...
Forecast adjusted towards blend of latest models. Tuesday to
Thursday surface high pressure and a building ridge aloft.
Temperatures stay above normal.
Thursday night into the weekend has much uncertainty. Hurricane
Matthew is moving north up the east coast. By Wednesday WPC has
this off of North Carolina. GFS has a faster and further west
track while Euro is off the coast with rain not in the CWA. The
Canadian is wide right. The track will greatly depend on the speed
of the approaching upper level trough and surface cold front. This
cold front in central NY and central PA on Saturday.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Terminals will remain IFR to MVFR through the forecast period as a
very moist low-level south-southeasterly flow remains in place
through Sunday morning. CIGs and VSBYs peak in the afternoon late
this afternoon and then drop to IFR all TAFs late tonight. As the
low-level winds turn more southwesterly above the surface layer
later Sunday morning we see some breaks developing in clouds but
CIGs will struggle to reach MVFR in most terminals before 18z.
Winds will remain east to southeasterly around 5 to 12 knots
through the period.
OUTLOOK...
Saturday afternoon-Monday...Occasional restrictions possible from
lower ceilings and scattered showers.
Tuesday-Thursday...Mostly VFR. Early morning fog possible at
KELM.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...TAC
LONG TERM...TAC
AVIATION...DJN
Area Forecast Discussion
National Weather Service Cleveland OH
619 PM EDT SAT OCT 1 2016
.SYNOPSIS...
Low pressure over northern Indiana will lift north into lower
Michigan overnight then shift east into Ontario on Sunday and to
New England on Monday. A large area of high pressure will move
across the Great Lakes Monday and move off the New England Coast
late Tuesday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Not much change in the forecast at this time. Upper level low has
moved to northern Indiana. Scattered showers will continue to
rotate through the area overnight. So, no significant changes
with this update.
Previous Discussion...
With the close proximity of the upper low
now over northern Indiana we can expect scattered showers with
isolated thunderstorms to continue or develop this evening. For
the next few hours before sunset...the highest coverage and
likelihood of showers will be over northwest Ohio where
instability is greatest and also over north central Ohio as a
small vorticity lobe seen in the water vapor over central Ohio
lifts north. Later in the evening...the confidence in timing and
location of convective development is lower. The HRRR has varying
amounts of showers with little run to run consistency so again
confidence is low. Overall guidance POPs are high but specific
triggers are difficult to discern. Will continue with chance to
likely POPs overnight with the higher POPs in the northeast.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
Gradual improvement in the weather can be expected during this
period as the upper low departs the region. The center of the
upper low will be near DTW on Sunday morning and move to near SYR
on Monday and off the New England coast on Tuesday. As the upper
low moves away, drier more stable conditions will develop and
decrease the chance for rain. On Sunday morning we can expect the
highest POPs over northeast Ohio and nw PA with a gradual decrease
during the day. Further drying can be expected Sunday night and
early Monday with just a lingering shower over mainly northwest
PA. Finally by Monday afternoon the forecast should be dry as high
pressure fully builds into the region. Fair weather will continue
Tuesday and Tuesday night.
Temperatures on Sunday will be just a tad cooler than today as
850mb temperatures will be 2-3C degrees cooler. A slow warming
trend can then be expected with readings at 850 mb warming to
around 12C which will boost surface max temperatures into the 70s
for Tuesday.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The next cold front will approach the area later in the week. It
looks as though most of the models are showing a weakening front
advancing across the northern Great Lakes on Thursday. This front
will likely not cross the forecast area or perhaps just the
dissipating version of the front. Then we wait for a stronger front
to arrive.
The second front may get here on Saturday although not a lot of
confidence yet until we get the east coast tropical system out to
sea. Cannot rule out a shower getting to northwest Ohio on Thursday
but will cut back the pop to "slight chance" for Thursday across
northwest Ohio. A somewhat better chance for showers Friday night
into Saturday but will keep the pops modest for now given the
uncertainty on the timing of the front.
Raised forecast temperatures through Friday given the potential
slower arrival of the front. Highs in the 70s, could turn out to be a
real nice week.
&&
.AVIATION /18Z Saturday THROUGH Thursday/...
No organized showers developing as of early afternoon. Cannot
rule out a pop up shower anywhere this afternoon but specifically
included it in the forecast at KTOL and KFDY which are near the
upper low. There seems to be a short wave rotating north across
the Ohio Valley and went with the idea that a batch of showers
will spread across the central and eastern parts of the forecast
area overnight with MVFR showers and local IFR ceilings and
visibilities toward daybreak. In any case, expect MVFR
cumulus/stratocumulus to develop Sunday morning with the daytime
heating Sunday.
OUTLOOK...local MVFR in showers Sunday afternoon and evening.
&&
.MARINE...
Weakening low pressure will drift across Lake Erie later tonight
and early Sunday and winds will veer from southeast to southwest.
There may be enough surface convergence for waterspouts but not
enough confidence to put them in the forecast and will have to
monitor the possibility.
High pressure will build across the lake early in the week and
ridging will persist through at least mid week. Winds will veer from
northwest to northeast and eventually southeast but remain relatively
light.
The next cold front will arrive late in the week but no confidence
on the timing yet.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...DJB/LaPlante
NEAR TERM...LaPlante/Lombardy
SHORT TERM...LaPlante
LONG TERM...Kosarik
AVIATION...Kosarik
MARINE...Kosarik
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
316 PM EDT Sat Oct 1 2016
.SHORT TERM...(This evening through Sunday night)
Issued at 315 PM EDT SAT OCT 1 2016
18z sfc analysis shows low pressure still holding over the Ohio
Valley beneath a gradually exiting upper low. These features have
been responsible for the plenty of clouds through the area once
again this afternoon along with sprinkles and a couple of
showers, though these were mainly confined to the northern and
western portions of the JKL CWA. Temperatures have made it into
the mid to upper 60s through the area while dewpoints are
generally in the low to mid 50s with light/variable winds.
The models are in good agreement aloft through the bulk of the
short term portion of the forecast. They all slowly take the deep
closed low north from the Ohio Valley and into the eastern Great
Lakes on Sunday. At this point, the model spread increases a bit as
the CMC scoots the low east faster than the consensus and has been
discounted - though the latest ECMWF seems to be a tad more
progressive than the rest, too. The departure of this closed low
will take its mid level energy with it, but not before Sunday
evening for most of the area allowing limited support for pcpn
around through the rest of the weekend. Given the model agreement
will favor a general blend with a lean toward the HRRR and NAM12
in the near term and some persistence mixed in.
Sensible weather will feature another cool and cloudy night with
sprinkles and a few showers around, similar to last night. Also,
like last night - anticipate fog for the valleys with locally
dense patches forming toward dawn. More clouds will be around on
Sunday with another potential for showers during the afternoon,
though most places will stay dry. Temperatures should be a notch
higher, as well. Look for another cool night into Monday morning
with a bit less in the way of clouds and as a result better
radiational conditions likely leading to more fog.
Used the CONSShort and ShortBlend as a starting point again for
most grids into Sunday morning with the SuperBlend used
thereafter. Made just some minor changes to the T grids based on
terrain with the clouds around tonight and slightly more changes
Sunday night. As for PoPs - ended up on the low side of a MOS
blend - closest to the MAV - through Monday morning.
.LONG TERM...(Monday through Saturday)
Issued at 300 PM EDT SAT OCT 1 2016
The extended portion of the forecast will be mostly dry, with very
pleasant temperatures through out. A ridge of high pressure will
influence the weather of eastern Kentucky through Thursday, with
partly cloudy to mostly clear skies and light winds expected across
our area. High temperatures each day through Thursday are forecast
to top out in the mid to upper 70s. A few locations may reach or
slightly exceed 80 degrees Tuesday through Thursday along and south
of the Hal Rogers Parkway and Highway 80 corridor. A cold front is
expected to move through the area Thursday night, bringing a few
rain showers to eastern Kentucky. Any lingering rain showers should
be exiting the area by late Friday morning. A much cooler air mass
is then expected to settle over the region to finish out the week.
Highs on Friday should be close to normal, with max values in the
low to mid 70s on tap. Nightly lows should bottom out in the 50s,
with readings in the mid to upper 40s possible for Friday morning.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 210 PM EDT SAT OCT 1 2016
The upper level low continues to meander across the Ohio Valley.
This will lead to bands of clouds through the period and the
threat of isolated showers/sprinkles, although the more
substantive of these should remain west and north of all TAF
sites. VFR to high MVFR conditions will be the rule through the
afternoon with southwest winds of to 5-10 knots. Winds will
diminish this evening as low stratus potentially develops near the
Bluegrass region and down towards Lake Cumberland. With the main
concentration of this and any visibility reductions again likely
centered north and west of all TAF sites so left mention out for
now, but did allow for some MVFR vis for a time at SME/LOZ and
SYM. VFR conditions should return by mid morning on Sunday with
light and variable winds.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
Area Forecast Discussion
National Weather Service Marquette MI
421 PM EDT Sat Oct 1 2016
.SHORT TERM...(This evening through Sunday)
Issued at 420 PM EDT SAT OCT 1 2016
WV imagery and RAP analysis indicated a mid/upper level low over
northeast Indiana and a ridge from the nrn plains to north of Lake
Superior. Radars indicated weak shortwave spokes to the north of the
low that supported bands of showers. At the surface, light northeast
winds prevailed between a ridge over nrn Ontario and low pres over
the s end of Lake Michigan.
Tonight, radar trends and short range models suggest that the area
of forcing to the southeast and 305k-310k isentropic lift will expand
back to the nw into the se half of the cwa during the evening.
However, enough dry air remains below 750 mb to limit the westward
extent of the pcpn. The clouds over the west may be thin enough for
radiational cooling and patchy fog. Otherwise, thicker mid clouds
will keep min temps from the mid 40s to the lower 50s central and
east.
Sunday, the mid level low will finally slide far enough off to the
east to the ern Great Lakes so that the pcpn will end and for skies
to gradually clear across the west half. However, there may be
some lingering light showers or sprinkles over the far east and south
early. With increasing sunshine, temps will remain above normal
with highs in the mid to upper 60s.
&&
.LONG TERM...(Sunday night through Saturday)
Issued at 315 PM EDT SAT OCT 1 2016
No precip expected Sun night into Tue as high pressure ridging is in
control. Could see fog Sun night as ridge is overhead, then again
Mon night (especially over the southeastern CWA) as SE flow
increase.
Next chance of rain is late Tue night through Wed evening as a
shortwave and cold front move through. Not guaranteed as the
system will be pretty volatile.
Quite a lot of uncertainty after Wed as models show a series of
potent system, but are not in agreement on timing/strength/track.
Given this uncertainty, just stuck with blends and allocated time to
fixing some AWIPS issues.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 152 PM EDT SAT OCT 1 2016
Expect VFR conditions through most of the period as mid clouds move
across Upper Michigan to the north of low pressure south of the
region. A few showers may affect SAW this afternoon and evening.
Late tonight some fog is also expected to develop at IWD as mid
clouds diminish.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 420 PM EDT SAT OCT 1 2016
A weak pressure gradient across Lake Superior through Mon will keep
east to northeast winds at 20 kts or less. Southeast winds increase
over 20 kts Tue into Wed ahead of front moving out the Northern
Plains. The strongest winds will occur over north central and
eastern Lk Superior. Behind the front on Thu, west winds may gust
to near 25 kts.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Titus
AVIATION...JLB
MARINE...JLB
Area Forecast Discussion
National Weather Service Pittsburgh PA
312 PM EDT Sat Oct 1 2016
.SYNOPSIS...
Upper level low will maintain shower chances through Sunday before
high pressure begins to build overhead for the start of the work
week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A shortwave pivoting around the broad closed low and convergence
at the surface will support showers and possibly a thunderstorm through
the rest of the afternoon. What has already developed over
western PA was progged well by the HRRR so opted to carry PoPs
that reflect this model. Widespread cu has developed with the
heating that was allowed earlier, but breaks in the clouds should
still let us realize temperatures in the low to mid 70`s.
The upper low will begin shift northeastward tonight with deep
southerly flow helping to keep temperatures up overnight. Unsure
as to how widespread cloud cover will be tonight as cu diminishes
with loss of heating. However, since low clouds were prevalent
around the low center this morning, have kept mostly cloudy skies
tonight.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Slow moving low will accelerate eastward Sunday, with the center
of the low moving into NY by evening. As it finally makes its
departure, some cooling aloft and support from a pivoting
shortwave should promote shower and isolated thunder development
Sunday afternoon, with the greatest likelihood north of
Pittsburgh.
Ridging will begin to build eastward on Monday but with our region
in the northwest flow between the ridge and the departing low,
some widely scattered showers may be possible. High pressure
should return dry weather no later than Tuesday. Building heights
and warming aloft should keep temperatures just above seasonal
averages.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Upper ridge will maintain it`s hold through Wednesday, but after
this time, forecast uncertainty increases as the model handle the
speed of the next upper trough and associated front differently.
At this time, it appears the GFS is the slowest, as it deepens
the trough more than the other models. Opted to take a model blend
approach, with emphasis on the ECMWF for now. Temperatures were
thus kept above average until the potential front passage Friday.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Conditions are quite variable across ports with bands of MVFR
clouds and light showers rotating across the region, with areas of
VFR in between. IFR at KDUJ should break out to MVFR or a time
late afternoon and evening before IFR returns overnight. At other
ports expect a conditions Sunday morning similar to this morning
as MVFR stratus develops after sunrise, with IFR possible at
western ports. With closed low transitioning across the eastern
Great Lakes Sunday afternoon expect a few showers, as CIGs slowly
improve in by afternoon.
.OUTLOOK /SUNDAY NIGHT THROUGH THURSDAY/...
Building high pressure will give general VFR into mid week.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
154 PM MST SAT OCT 1 2016
.SYNOPSIS...
This weekend will feature seasonably warm temperatures and mostly
clear skies though some breeziness will enter the picture by Sunday
afternoon. Increasing moisture across south central Arizona Sunday will
also lead to a slight chance of showers and thunderstorms mainly
from Maricopa County eastward. Dry weather will dominate the weather
pattern next week though a sharp cooling trend will arrive early in
the week as a strong area of low pressure passes to our north.
&&
.DISCUSSION...
Latest streamline analysis shows southwesterly flow between an
anticyclone near the southern tip of the Baja Peninsula and a closed
low off the Pacific Northwest coast. Conditions at the surface remain
more moist than normal across the Desert Southwest with dewpoints
generally in the 50s and isolated showers persist across mainly the
Mogollon Rim this afternoon. Latest runs off the HRRR continue to
indicate that this activity will dissipate before sunset, while
mostly clear skies prevail across the lower deserts.
General consensus among the suite of global and convective-allowing
models is that deeper moisture (1+ inch PWATs) currently residing
across the GOC will get drawn northward as the aforementioned low
pressure system drops into northern California Sunday. Increasing
vorticity and jet-forced ascent ahead of the low will result in a
narrow band of broken clouds traversing eastward across central
Arizona Sunday afternoon and evening. Model soundings suggest
relatively warm and dry conditions aloft will limit CAPE and
subsequent vertical development of any convection. Nevertheless,
conditions are favorable for at least some shower activity from
mainly Maricopa County eastward. PoPs were increased to around 20
percent for the Phoenix area and up to 30 percent across southern
Gila County. With the expected increase in moisture/clouds, latest
temperature guidance came in a few degrees lower and forecast
temperatures were adjusted accordingly.
&&
.PREVIOUS DISCUSSION...
The deep Pacific trough to our northwest will eventually lead to
breezy and much cooler conditions as a cold front pushes across the
deserts Monday and a much drier westerly flow aloft will follow into
the early to mid part of next week behind the exiting trof. Latest
GFS and ECMWF runs as well as GEFS ensembles support this basic
idea.
One additional note; on Sunday we can expect windy conditions across
southeast California as low level gradients tighten ahead of the
advancing low. Winds should remain remain below wind advisory
criteria for the most part but a few favored locations such as areas
to the southwest of Imperial may see gusts reaching advisory levels
for a short time. Winds will also lead to potentially dangerous fire
weather conditions for a few hours as well given RH values will drop
to around 15 percent during the afternoon.
Later Sunday night through Monday the main upper low center is
forecast to progressively move east and pass by well to our north,
moving through central NV and Utah. Following the passage of the
cold front, high temperatures over the deserts will fall into the
80s; Phoenix will drop to around 85 degrees, almost 10 degrees below
the normal of 94. Except for a lingering 10 percent chance of a
shower or storm to the east of Globe, much drier westerly flow will
rapidly overspread the deserts giving sunny skies on Monday. On
Tuesday, as the low quickly ejects off to our northeast, dry
subsident northwest flow will move across the area for continued
sunny skies along with much cooler than normal high temperatures.
High temperatures Tuesday should remain in the middle 80s across the
greater Phoenix area.
For Wednesday through Friday, following the exit of the Pacific
upper low, dry and relatively zonal flow will spread across the
desert southwest leading to mostly sunny or sunny days, clear nights
and warming temperatures. Highs over all of the deserts will rise
back into the 90s by Thursday with mostly mid 90s expected over the
warmer deserts on Friday.
&&
.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL:
After relatively quiet period from this evening into Sunday morning,
with just few-sct mid-level cloud layers and typical diurnal winds,
increasing mid and high-level cloudiness can be expected during the
midday and afternoon hours on Sunday as a cold front approaches the
region from the northwest. This front is expected to increase the
usual westerly breezes somewhat on Sunday afternoon, with wind gusts
as strong at 20 knots possible. Along with the wind, the front is
also forecast to produce isolated-scattered shower/thunderstorm
activity over the region, with a 20-30 percent chance of
showers/storms affecting any one given location. At this point,
however, confidence is still too low to put -shra/-tsra in any of
the Phx area taf sites.
Southeast California/Southwest Arizona including KIPL and KBLH:
A relatively dry airmass and stable conditions will keep skies
mainly clear at both SE CA taf sites, except for a band of few-sct
mid-level clouds moving across the region during the
midday/afternoon hours on Sunday as a dry cold front moves through.
Winds to remain mainly from a westerly direction at KIPL and a
southwesterly direction at KBLH through the taf period. Relatively
light winds at both taf sites tonight and early Sunday to give way
to stronger winds on Sunday afternoon as the aforementioned front
posses through, with wind speeds as high as 20 kts and gusts to 30
knots possible by late afternoon.
&&
.FIRE WEATHER...
Tuesday through Saturday:
Relatively dry air moving in from the west to keep skies mainly
clear through the entire period. Winds to remain on the light side
for the most part, except for somewhat stronger winds during the day
on Wednesday, when a weak weather disturbance passing off to the
north helps to mix stronger winds down to the sfc. Humidities to
fall into the high single number-teen range each day. Overnight
recovery will only be fair. Highs in the 80s across the lower
deserts on Tuesday to rise into the low-mid 90s by Thursday, then
hold in that range through Saturday.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation will not be needed.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
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DISCUSSION...Hirsch
PREVIOUS DISCUSSION...CB
AVIATION...Percha
FIRE WEATHER...Percha