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000 
FXUS61 KBUF 191949
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
349 PM EDT Sat Oct 19 2019

.SYNOPSIS...
Splendid weather for viewing the peak of the Fall foliage 
continues as high pressure passing to our east will provide us 
with us with fair dry weather through Monday. The pleasant 
weather will be accompanied by day to day warming with 
temperatures climbing as high as the lower 70s across the 
western counties for Monday. A dramatic change back to more 
seasonable Fall weather will then take place for the remainder 
of the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
A bit of fair weather cu earlier but skies have become sunny across 
the region this afternoon. After a frosty start which likely ended 
the growing season for all but a select few locations, temps have 
reached the 50s this afternoon. High pressure remains over the 
region tonight into Sunday. May see some mid to high clouds 
associated with remnants of post tropical system Nestor clipping 
Finger Lakes later tonight into Sunday morning. Does appear that 
rain with this system should stay over far southeast NY toward NYC 
and Long Island. Weak return flow and some clouds tonight will allow 
temps tonight to be warmer than last night with mainly lower 40s 
expected. Favored cold spots could see readings into the upper 30s, 
with even lower 30s east of Lake Ontario closer to the sfc high 
axis. 

Skies will start off mainly sunny on Sunday, but mid to high clouds 
will begin to increase in the afternoon over western NY as shortwave 
trough swings across the Upper Great Lakes. Will also see the clouds 
over the east slowly depart through the morning. Increasing H9-H85 
temps will result in high temps reaching the lower to middle 60s, 
with readings around 60F east of Lake Ontario.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Sunday night, our region will remain under the influence of the 
surface high extending from James Bay south and east across New York 
State. Meanwhile, our next weather maker will be in the process of 
exiting the Rocky mountains and beginning to track east across the 
Upper Midwest. Otherwise, with the surface high influencing our 
weather expect generally clear skies and light wind flow overnight. 
This will also allow for good radiational cooling to take place with 
some river valley fog formation. Look for lows in the lower 40s 
inland away from the lakes with mid to upper 40s along the lake 
plains.

Low pressure will then track out of the Upper Midwest and arrive 
across Lake Superior by late in the day on Monday. As this feature 
tracks into the Upper Great Lakes warm advection processes and 
southerly flow will pick up across the forecast area. This will aid 
in sending our temperatures up well above normal with upper 60s to 
the lower 70s across the lake plains. Overall, it should be a fine 
fall day across the area with plentiful sunshine expected for a good 
portion of the day. It will make for a perfect day to get out and go 
see the fall foliage, especially to go see Letchworth State Park 
which is near or at peak.

The surface low over Lake Superior will slowly drift northward into 
southeast Ontario Canada and mature Monday night. As it does so, it 
will slowly pivot its trailing front into and then slowly east 
across New York State. As the front crosses the forecast area it 
will bring an area of widespread rainfall to the area for a good 
portion of the day Tuesday. In regards to rainfall amounts, most 
locations should expect to see rainfall totals come in just under an 
inch. Behind the front, widespread rainfall will taper off along 
with winds veering around to southwest. Also, over the course of the 
day H850T will cool and are forecast to drop per ECMWF/GFS/NAM from 
+12C to ~+2/3C by Tuesday evening.  

The steadier precipitation should all be in the process of winding 
down for our forecast area by early Tuesday night. Behind the front, 
the atmospheric column will continue to cool. This in combination 
with the broad mid level trough wrapping additional moisture in 
across the lower lakes will support lake effect showers northeast of 
both lakes. However, it will only be a brief window for lake driven 
rain showers given the fact that synoptic moisture gets quickly 
stripped away and equilibrium levels drop by Wednesday. With that 
said, this event or setup will be somewhat similar to last 
Wednesday. In that event some lightning and graupel was observed 
within the stronger rain showers. Current BUFKIT forecast profiles 
do show lake induced equilibrium levels climbing to near 21K for 
this next event. Additionally, the depth from the surface to -10C 
will be nearing 10K, which is another key ingredient. So it's not 
out of the realm of possibility that some of the stronger showers 
will again be able to produce lightning and graupel. Stay tuned! 

Behind the front it will be markedly cooler with highs by Wednesday 
expected to only top out in the 50s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
The pressure gradient between low pressure across Hudson Bay and 
high pressure across the mid-Atlantic states will result in a 
general southwesterly flow across the region Wednesday night and 
Thursday. Initially it will be cool enough aloft to support some 
lake effect rain showers Wednesday night, then these may be followed 
by more showers with a subtle shortwave embedded in the flow aloft 
on Thursday. This said, showers will be scattered in nature and the 
majority of the time will be cool and dry.

After this, 12Z model guidance continues to differ with the GFS/GEM 
slowly moving a shortwave across the region while the ECMWF has a 
cut-off low developing across the southern states. If the former 
verifies, there will be a period of rain Friday into Saturday as low 
pressure develops in response to the shortwave. It also would result 
in cooler conditions on Saturday when there would be a northwesterly 
flow behind the system. The ECMWF solution would lead to a mainly 
dry and slightly warmer pattern. Given the resulting forecast 
uncertainty, have kept PoPs in the chance range until model guidance 
comes to a better consensus. Temperatures will not stray too far 
from normal for late October with daytime highs mainly in the 50s.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
Looking at ideal flying weather through Sunday with VFR conditions 
and light winds. Think scattered to broken incoming high clouds may 
limit fog coverage in the Southern Tier, so have no mention at JHW 
tonight. 

Outlook... 
Monday...VFR. 
Tuesday...MVFR with areas of rain and fog.
Wednesday...MVFR to VFR with scattered lake effect rain showers 
northeast of Lakes Erie and Ontario.
Thursday...VFR.

&&

.MARINE...
As surface high moves across New England through Sunday...a weak 
pressure gradient will remain in place across the Lower Great lakes. 
This will maintain light winds and negligible waves through the 
remainder of the weekend. 

East to southeast winds will begin to freshen on Monday...well ahead 
of a slow moving cold front that will be crossing the mid-western 
states.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...JLA/RSH

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