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Sunday, October 20

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Good Sunday morning!

Did you get any rain? It appears that most of north Georgia received some rain, some more than others. I just made my CoCoRaHS report this morning (I had 1.68" here in Gwinnett) but saw a 1.89" at Rabun Gap and 1.79" about 9 miles NW of Blue Ridge. The reports will start coming in very quickly now, so I'll give you a better update with a map then. The radar estimates are way off for several reasons. One, much of the rain that fell came from clouds below the radar beam, especially from those areas that are further away from the radar. The other reason was that  the small size of some of the water droplets (misty and light rain) makes it more difficult for the radar to pick up. Here is the radar estimated view. It says I only had 0.75", so WAY under done. The greens are up to 0.50" and blue 1-2".atl_radar-20.thumb.png.202558454a49060b64713c39ff117b03.png


Here's a big picture look at the US this morning. You can see the remnants of Nestor getting blown up the coast as well as our next big weather maker and our Mon/Tue cold front taking shape over the western US. That trough is expected to form a closed low over the plains and create a strong cold front that will bring severe weather over the plains tomorrow.



Our focus now turns to the next two systems that are on the map. The first one comes in Tuesday and then another possibly stronger one next weekend. The best part of this news is that there is the potential for another 3-4" of rain across north Georgia over and above what we just had.

I wanted to share this part of the WPC Extended Forecast Discussion from this morning pertaining to the setup.


Height falls should then act to carve out an amplified central
U.S. upper trough later week.
Pattern evolution uncertainty grows
quickly however, lower forecast confidence. Latest guidance trends
are mixed, but there is an overall signal showing southern stream
separation to some degree later week into next weekend as the main
trough shifts over the central states with a possibility of closed
low formation
that would drastically up the ante with respect to
subsequent rainfall potential and runoff threat from the South
northeastward into the Eastern Seaboard with deep return of Gulf
of Mexico and Atlantic moisture
. WPC progs have trended to show
such potential
. This is with consideration of the amplitude of
upstream upper ridging and as the next main kicker upper trough
does not bring unsettled weather/locally enhanced precipitation
through the Northwest until next weekend, so wavelength spacing
with the downstream system seems sufficient to allow for at least
some southern stream separation.

They are talking about next weekend. I just took a look at all the models this morning and wow, what an active pattern coming up. Lots of chances for rain and below normal temperatures over the next several weeks.

Today will be the warmest day this week with our temps jumping up pretty dramatically from yesterday's highs as moisture begins to return in advance of our late Monday night/Tuesday cold front. The timing of the front is such that the heating of the day will not be a factor (night time passage) so the thunderstorms will not have the necessary energy to get as strong as they might have gotten otherwise. Here's the WPC Severe Weather outlook for Monday and you can see the worst of the weather is far to our west, and we're not even on their map for Tuesday.



The front will bring rain for us and "right now" these are the projected rainfall amounts from the Weather Prediction Center through 8 PM Wednesday.



But when we look ahead to next weekend we start to see those totals build. From Friday the 25th 8 AM through Sunday 8 AM, these are the expected 48 hour totals. For NOW. 😉 You know... things can change. 1720982571_48hourrain8amfri-8amsunday.thumb.png.ff4fea79d2a96e3734c8a8bf6c1fe9b1.png


And that would bring the 7 day grand total to something like this.



So we'll see how all of this evolves this week. I love active weather periods, you have all kinds of stuff flying around and that always leads to surprises down the road. 🙂

I hope everyone has a great and dry Sunday! Enjoy this fall weather! 🙂

Winter begins in 63 days.

The dead leaves fall like noiseless rain,
The air is calm and warm and sweet;
Upon the woodland and the plain
The ghost of summer rests her feet.  

–Clinton Scollard (1860–1932) 
The Old Farmer's Almanac


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Larry Cosgrove's Long Term Forecast


In lining up the variables for my winter forecast, I feel fairly safe with the idea that the ENSO signal will be close to flat neutral. I say this because virtually all of the modeled forecasts for Pacific Ocean sea surface temperature anomalies show a very steady register just above the zero deviation line. You will notice also that there is a very strong cold signal over and just to the left of the Maritime Continent. If this anomaly persists, the Madden-Julian Oscillation will probably be strongest from Phases 7, 8, and 1. And should the MJO convection groupings tend to feed (connect/link) with the polar westerlies, it is reasonable to figure that stronger pulses of amplification in the jet stream will result in more cold intrusions through North America as we head into calendar winter.

But climatology also implies that an "Indian Summer" will take shape in November, a common theme seen in recent autumns. I lean toward a mild West vs. cold Central vs. transient East set-up for the first week of the new month. The CFS series has been very aggressive with a semizonal flow and a nationwide warm-up for the middle two weeks of November. The European weeklies, however, are not as bullish on the warmth, preferring to maintain a warm West vs. neutral/cool East alignment. It makes sense to blend the two themes, So after a fairly chilly domain east of the Rocky Mountains through November 7, I suspect that most of the lower 48 states will be mild, locally on the warm side, until we approach Thanksgiving. What could mess this idea up? The tropics, whether it be from a northward recurving Typhoon over the western Pacific Ocean. Or, perhaps, a disturbance that brews over the still very warm waters of the Gulf of Mexico, Caribbean and Sargasso Seas.

I also want you to look at the snow and ice charts for North America and the Northern Hemisphere as a whole. You will note that there is not much coverage of frozen types anywhere near the Arctic Circle, and even Eurasia snowpack looks fairly lame in comparison to previous years. So even when the U.S. gets into impressive cold air drainage, the travel of the regime over so much bare ground is going to prevent the air mass from acquiring much "night radiation drop". Hence the words "cool" and "chilly" are advisable, as opposed to cold. And as we prepare for the start of the holidays, it seems probable that the truly frigid air will not be in evidence until December rolls around.
Prepared by Meteorologist LARRY COSGROVE on 
Saturday, October 19, 2019 at 9:15 P.M. CT


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