Tuesday: Mostly sunny. High temperatures in the upper 70s.

Wednesday: Mostly sunny, slightly warmer. Early low temperatures in the upper 50s, slightly cooler in the valleys. High temperatures in the low 80s.

Thursday: Rain in the  overnight; clouds and sun by daylight. Lows in the low 60s. Highs in the mid-70s. Lows heading into Friday morning in the low 50s.

Friday through Monday: Friday and Saturday look to be dry, mostly sunny and comparatively cool. Afternoon highs for those days will likely hover around 70, possibly in the low 70s. Low temperatures will be around 50. As Cattaraugus County Fair week approaches, the models are suggesting an increased chance of precipitation but a slight bump in high temperatures into the mid-70s. This is associated with a wind shift that will bring warmer, more moist Gulf air over the region. It won’t be hot and sticky like the past couple of weeks, but it’ll raise the threat of convective thunderstorms (it does not appear to be an organized front).

Long range: GFS pushes a body of fairly (i.e. easily more than half an inch) heavy rain across the Great Plains (quite quickly) into the area on Wednesday, August 4.

Climatologically speaking: The slide begins. As I stated in a previous post, July 22 is the day of peak temperature, climatologically speaking, in Little Valley. As the days begin to get shorter and shorter, less daylight, and less direct daylight, begin to lead temperatures downward. It doesn’t begin to have significant effect until August, but as far as high temperatures go, it’s (generally) all downhill from here. We notice that with the beginning appearances of cold fronts this week. This doesn’t rule out more hot days like we’ve seen earlier this summer, but they will be fewer and farther between as August progresses.

As of midnight 7/25, the list of storm reports from the NWS can be found here.

~J. M. Fuller

These thunderstorms are sandwiched between the Lake Erie lake breeze and the Lake Ontario lake breeze. These two colliding breezes show up beautifully on satellite imagery as the low level flow is indicated by the yellow arrows in the image. This convergence in addition to the already warm and soupy airmass already in place, was more than what was needed to get things firing.

As the evening wears on, this area of activity will die down as both lake breezes fizzle out; however, we still have a cold front on our doorstep that may develop more thunderstorms a little later this evening. Could see more strong winds and heavy downpours.

In other news, I’ll be out of town beginning tomorrow morning until Sunday evening so I’ll be unable to update any of the forecasts.

Tuesday night into Wednesday: Mostly cloudy. A chance of some scattered showers in a few places, but these will likely be very sporadic. Early lows in the low 60s. Afternoon high temperatures in the upper 70s.

Thursday: Mostly cloudy for the overnight, with clouds breaking and partly sunny skies during the day. Early low temperatures in the upper 50s. Afternoon high temperatures around 80.

Friday through Monday: Rain comes in as the core of a low pressure mass moves across the northern plains and reaches the Twin Tiers on Friday. It will likely continue to bring precipitation through Saturday. The two models seem to disagree over whether or not the bulk of the rain will be on Friday (as the NAM suggests) or if a second wave of precipitation will push through on Saturday night (as the GFS suggests). Either way, the sum total of precipitation should be between 0.5″ and 1.0″. High pressure is expected to push back into the area for Sunday and Monday. In regard to temperatures, they should remain fairly steady, with low temperatures in the low 60s and high temperatures in the low 80s.

Long range: The outlook for July 27-29 looks much like the two days preceding it; high pressure will likely remain in place through that time period and temperatures will likely remain fairly steady.

~J.M. Fuller

Sunday Night
Radars upstream of us over the upper Great Lakes show plenty of on going showers and thunderstorms as of Sunday afternoon. They should hold together as the move to the east and will be on our doorstep after dark. A few weak showers are out ahead of this activity, so a passing sprinkle or two is possible for the remainder of Sunday.

Monday
Monday will be an active day with passing showers and thunderstorms, especially before 3pm. There may even be some clearing by early evening. Temperatures will mainly in the upper 70s.

Tuesday
Partly to mostly sunny skies during the morning will give way to increasing clouds, similar to the day on Sunday. May even see a few showers by late afternoon on Tuesday. Highs in the upper 70s again.

Wednesday/Thursday
High pressure begins to build on Wednesday leaving us with mostly sunny skies, low humidity, and comfortable temperatures right around 80. Same forecast for Thursday, but a degree or two warmer.

Anyways, the weather setup as of midday Thursday looks like this. A low pressure system over extreme north western Ontario is moving southeast, but will still remain well to our north. Its associated warm/cold front will both cross our area over the next 24-30 hours or so. In fact, based on current surface conditions, it looks like the warm front has already lifted north of Lake Ontario. Temperatures and dew points are both climbing leading to a warm and sticky afternoon. With the cold to our west (Chicago area now), it will be a warm and muggy night heading into Friday.

On Friday, the “cold” front will move through, but temperatures on each side of the boundary are not significantly different; however, dew points are much lower behind it. With the passage of the front, showers and thunderstorms can be expected on Friday, mainly during the morning to early afternoon. Will need to keep an eye out for a few more slow moving thunderstorms, especially with all of the recent rainfall. Flooding could be a concern.

Friday
Showers and thunderstorms will be crossing the area. The best window for this activity will be between 7am and 2pm. Again, a few storms will be capable of dropping an inch or two of rain in a short period of time. Look for an evening high in the mid 80s as I think we might break out into partly to mostly sunny skies for the late afternoon.

Saturday
On Saturday, just a small chance of an afternoon shower or thunderstorm. The models show a weak front dropping south and cannot rule out a wayward storm or two developing. Not everyone will get in on this action though. Otherwise, temperatures will climb back into the mid to upper 80s.

Sunday
And finally, for Sunday, expect mostly sunny skies. Temperatures will be within a few degrees of 90.

Now, as for the Twin Tiers Ten-Day Forecast…

The National Weather Service has issued a Flash Flood Warning for portions of Allegany County around and east of Rushford, due to heavy downpours.

Tuesday: Mostly cloudy, with isolated convective thunderstorms. Afternoon highs in the upper 70s.
Wednesday: A few scattered showers possible, but unlikely, in the overnight hours, then skies clearing in the afternoon. Early lows in the low 60s. Afternoon highs in the low 80s.
Thursday: A clear, calm, cool night, followed by a hot, hazy day. Early lows in the low 50s in the valleys, upper 50s elsewhere. Afternoon highs in the upper 80s. Winds shift into a southerly direction.

Friday through Monday: GFS is forecasting a low to move well to our north but bring a weak “cold” front across the region on Friday, with the possibility of precipitation. Gulf moisture becomes the bigger threat for Saturday as a weak southwesterly flow pushes a separate body of light rain into the area. Sunday, on the other hand, should be dry, as should Monday. Low temperatures are likely to remain in the low 60s throughout the period, but high temperatures will hit the low 80s on Friday before dropping into the upper 70s from Saturday through Monday. In PA regions, where the southerly wet flow should remain more dominant, temperatures could easily remain in the low 80s.

Long range: Both the GFS and the ECMWF forecast the jet stream to establish a zonal flow over the region in the 8-10 day forecast period. GFS forecasts a surface low pressure system to work its way into the jet and swing its way over the area on Tuesday or Wednesday. It’s too far out to predict how much precipitation it can produce, but it’s a fair guess to say it will be significant. Temperatures should remain fairly steady in the low 80s.

Mid-July is, climatologically speaking, the hottest month on the calendar in the western New York/Twin Tiers region. It is also the one where high temperatures are relatively stable. The average high temperature for the Little Valley station is 78 for every day between July 5 and August 5, with the exception of July 22, which peaks at 79.

Plenty of showers and heavy thunderstorms out ahead of the front with passing heavy downpours. Some locations have likely picked up between 2-3″ of rain already today, and there’s more to come. As of 4pm, about 3/4″ are officially in the bucket at the airport.

After this front is east of us, precipitation will come to an end as drier air quickly fills in. Looking upstream from here, dew points range from the low to upper 50s out across the upper Great Lakes indicating comfortable air. We will tap into that air-mass for the upcoming weekend.

As of right now, it doesn’t look like we’ll see the mid 90s again for a little while, but temperatures this weekend and early next week will still be above normal.

Saturday
With all of the rain we’re receiving on Friday and Friday night, there will be plenty of low level moisture around Saturday morning. Dense fog could be an issue, especially south of the Thruway. Any fog will quickly burn up leaving us with mostly sunny skies. Certainly much more comfortable on Saturday with afternoon highs in the low 80s.

Sunday
Sunday looks great. Mostly sunny again, low humidity, and temperatures in the low 80s. Perfect day for any outdoor activities.

Monday
The flow turns a little more southwesterly. We’ll see an increase in humidity, but shouldn’t be as bad as it’s been. The mercury will climb back to near 90. Remaining mostly sunny.

Venus is often considered the Morning Star or the Evening Star, depending on which time of day it is up and dominating the darkness. For example, from mid-February to mid-October 2010, Venus will be the most notable object in the evening sky in the west after sunset. It shines at a stunning -4 magnitude. The only natural objects in the night sky that are brighter than Venus are the Sun and the Moon (Satellites can briefly flare brighter than Venus).

Because Venus is close to Earth, it does not twinkle, as a star does. Its bright white light will hold steady, while if you compare stars in the vicinity, they “twinkle” or seem to waver and even change color.

Venus goes through phases like the Moon because of its position between Earth and the Sun. When it is more of a crescent phase it is closer to us and bigger, and also its angle makes it look farther from the Sun and places it in a darker sky. For these reasons, Venus is brighter in its crescent phase than when it is near full phase! The crescent phases of Venus can be detected through binoculars or a telescope. Look for a large thin crescent at dusk in September and early October 2010.

~Kelly Whitt

Basically, from Friday to Tuesday, the forecast will be vary similar day to day with mostly sunny skies and temperatures climbing into the low 90s starting on the 4th of July and maybe even mid 90s on Monday or Tuesday. Humidity levels will be low on Friday and Saturday, but by Sunday, it will really begin to feel tropical.

The combination of temperatures in the 90s and dew points increasing into the 60s, the heat index will be in the upper 90s to near 100 degrees. Last summer, we only had one day that hit 90 degrees, 90 exactly so it’s been some time since we’ve seen these kinds of readings.

Overnight lows Sunday night into Monday and Monday night into Tuesday won’t make it out of the 70s, so buy those fans or A/C units now.