Welcome to your Thursday :-)
Sunshine is back today-- did you miss it?
So just ignore the bit about Brooklyn, substitute "Kotter" for sunshine, and you've got it ;-)
We may be a little slow out of the gates in the mountains today (it happens with regularity on a morning clear-out), but most everyone should get to sunshine fairly quickly in the day. Here's the simulated Rad/Sat on this:
|NAM - 4km Simulated Radar - Thursday 8am||NAM - 4km Simulated Radar - Thursday 2pm|
Once these clouds break, we will enter into an environment dominated by high pressure. Just like low pressure has winds spiralling cyclonically into it (creating convergence and lifting of air), the high pressure system has sinking air that spirals outward from it (causing divergence and clearing). This will be at work overhead as plenty of sun is in the forecast straight through Saturday. As we've talked about for a few days, there is but one problem with it: Radiational cooling.
---Small Tangent about radiational cooling... feel free to skip---
Anything and everything in this world radiates heat energy outward. For example, if you don't believe me, step into a crowded elevator and wonder why it's always so hot in there ;-) ... The thing is, it just depends on your surroundings. If the Sun is shining bright, you are going to be warming up as the heat energy coming off you is trying to balance that which is coming in. When you're out on a cold day, you instead are cooling off, as the atmosphere is not providing any incoming warmth (either extreme therefore can naturally become hazardous). With "radiational cooling", the Earth is doing its thing and radiating heat energy based on how it had warmed during the day. The absence of clouds, wind, humidity, etc. permit this heat energy to simply continue to radiate outward from the Earth's surface, providing for maximum cooling. If we were able to sneak in some clouds and such, this would redirect some of this outgoing radiation back down to the Earth, providing a small buffer that mitigates the strength of the cooling. Radiational cooling can be enhanced by terrain and vegetation as well-- if you want to see a startling example of radiational cooling at work that's relatively near us, check out a little ditty on the "Barrens" microclimate that's just a hop, skip, and a jump from Penn State's main campus. When I was in college getting my undergrad (at Penn State), one of the "fun" things some of the other meteorologists did was to head out to the Barrens on a particularly cold night with a thermometer to see how cold the temperatures got to. Needless to say I never understood that ;-)
Here's the surface map leading up to Friday night's weather:
My personal preference for the "coldest night we'll see out of the bunch" would be this very set-up: An area of high pressure centered real close, but just to the west of the area. The fact that we're just about underneath the core means that we will get as few clouds/wind as possible. The idea about being to the east of it means that whatever wind flow we do get will still funnel cooler air into the area. Perfect for radiational cooling. So how cold is it going to get Friday morning. When a situation calls for it, meteorologists can stare at 'extra stuff' to make a more informed decision. Here's what we'll look at:
|NMM - Temperatures - Friday AM||AVN - Min Temps - Friday AM||NAM - Min Temps Friday AM
(Feel free to click on any map for a larger image). Now, with these maps, naturally the middle one jumps out at you a little bit. The AVN model is wanting to put down upper 30s locally, while the others want to keep us out of that territory for the most part. In this situation, we can do a number of things: 1) Go with the coldest for the most alarm to cover us and the viewer; 2) Average them out equally to get a 'consensus' value; 3) Institute a weighted average mentally based on how these models have been performing recently; 4) Simply come up with a number without doing any such calculations, being generally informed by these maps and your general knowledge of the area and its weather history. I can tell you that all of these methods have been in operation at one time or another depending on the situation. I suppose further discussion could go on forever and get quite philosophical. Tony and I have come to the conclusion that we'll be going with 40 for a low in Huntington, though 39 is not out of the question and could be chosen just to emphasize the possibilities of frost. The best chance for frost will be in the mountain valleys well to the east though (out of our viewing area). However, if you have got plants to put in, I would definitely wait until after about 9am on Friday and then you're home free!
As stated earlier, the good news is (for moms who are planning on "supervising" others laboring in the garden) we'll be dry through Saturday. Mother's Day itself may not be too great, but if you get everything into the ground before-hand, having some natural water feed the plants is just the ticket compared to sweltering outside holding the hose. When the rain returns though, expect to go through another 'zone' of turbulent weather. Showers will actually stick around for a few days:
|GFS - Sunday PM
||GFS - Monday PM||GFS - Tuesday PM|
After the initial front moves in, notice how the angle of if is not North-South, but instead a forward-folded Northeast-Southwest. This is a good indicator for an eventual stall-out. Those mountains love to do wonders with systems like this and not allow them to finish strong. Future impulses of energy would ride along the boundary and flare things up all over again. Currently the idea is that we'll be back to the patchy rain starting Sunday night, with the risk continuing into Wednesday.
|Regional Radar/Satellite with Warnings Tracking||
|Temperatures||HD Doppler Radar||Estimated Rainfall||Active Warnings|
|Click For Larger||Click For Interactive Radar||Click For Larger||Click For Larger|
Have a great day everyone!