Windspeed

Training cells are definitely a concern into the evening. Some portions of Sullivan Co. are pushing 2" already. Hopefully this convection can lift over the Apps. in a hurry.

Small cells keep passing over each hour but heavy rates with each one. Ground is pretty saturated. If coverage starts to expand this evening and train over the region tonight, I expect there will be some flooding streams. MWX just put out an advisory as well...

lol, someone hurry up and notify Dr. Klotzbach that he needs rejustify and explain his numbers again for the ASO on July 26th. There is a climatological genius on AmericanWx that demands it. [emoji849]

The Sub-Saharan Air Layer (SAL) is commonly active during peak Summer months due to positioning of the Azores semi-permanent subtropical ridge placement. Azores ridging tends to be strongest May through August and until it retrogrades west with an increase in western Atlantic (WAR) 600dm heights, which generally takes hold by September. It's generally back and forth in August leading into ASO ridge placement. Therefore, it's quite common to see lifted Saharan dust get pulled across the Atlantic basin and MDR when Azores ridging and Saharan ridge are strong and conjoined. We do still see plumes advance as late as September, but waning during peak CV/MDR portion of the Atlantic tropical/hurricane season. So nothing out of the ordinary about SAL so far this year. And yes, SAL can definitely have a negative effect on tropical activity in the MDR when present and particularly strong.

Thanks for the correction. Yes, the ENSO index hit +.7 in August '04, so technically a weak Nino. No idea why I thought that was a Nina year. We had some powerful MDR long-trackers that season though with the strong +AMO. Essentially an ENSO index around neutral to slightly positive or weak has been in place during some very hyperactive years, so there does not have to be a strong -ENSO/La Nina in place for the Atlantic to produce them, though certainly having a decent +AMO is ideal.

It's July 17th. If you want to buckle down on what ECONUS mid-level flow will be like on August 17th from what it looks like today, least I remind folks that 2004 saw a very similar pattern in July during a -ENSO. Even our first major hurricane got hooked right into a strong mid-August trough. Then the pattern flipped and all hell broke loose. Interestingly, there was a pretty active June-July in the EPAC that year even with a -ENSO in place. Of course, again, it shut down and an epic WAR/AMO took over by August 31st. That does not mean we'll see a similar outcome, but clearly NINO 4 is bottoming out again and +PNA ridging may not last until the end of Summer.

If I am making a call at this point, I think the CSU forecast analysis for this season is still in-line with predeterministic long-range modeling. I do not foresee a slow increase into the meat of September, but instead a "flip of the switch" by late August that unleashes a hyperactive stretch that's busy busy busy well into October. Hopefully there will be some lingering troughyness in the ECONUS that can recurve potential TC threats, but if these TCs are traversing the Caribbean, anything is on the table including GOM/Florida systems. Buckle up, it's going to be a bumpy ride.

RE: Seasonal precip and SST ensemble anomalies for the height of the season, August-October. This pattern suggests very active MDR-Caribbean AEW tracks with greater instability/lift in the tropical versus subtropical latitudes that would be prone to sinking air/ridging. This may be indicative of CV long trackers at a lower latitude. It may also be suggestive of more southerly TCGs and a higher threat to Caribbean and Central American landmasses than the ECONUS. But short-term pattern changes for tracking are not easy to forecast in the long range, (i.e. a specific digging trough vs amped ridge here and there). All in consideration, this isn't the look you want if you're targeting a dead MDR/CV stretch of the Atlantic hurricane season. Again, per the earlier discussion, whether we have Mid-Atlantic/New England threats doesn't bank on whether we have a hyperactive season. The Carribean through Central-American landmasses may be under the gun this year. And obviously anything that slips into the WCARIB/Bahamas increases potential for the SECONUS dependant on timing of WAR heights.

"Pushing the season back to late August.." You cannot push back the unexpected. Nearly every hyperactive season on record has the same thing in common. Most see nothing out of the MDR prior to mid August. 2005 is always going to be the rarest anomaly in that we had multiple early major hurricanes traverse the Caribbean. Of note, Bonnie's track a few weeks ago was merely a few ticks shy of giving us a late June Caribbean-runner major hurricane. Whether it did or didn't, the impact is minimal versus the overall climatological record however. There is little correlation between early Atlantic activity vs the MDR/CV season. That being said, dead Atlantic tropical seasons usually show their hand around this time based on pattern indicators. That is not the case at present as current signals suggest robust instability across the MDR from mid-August to early October. Now whether the ECONUS pattern favors landfalls or recurves remains to be seen. But it looks to be a busy season for tracking MDR canes. Of recent trends, the SST anomalies are leaning into the MDR/CV wheelhouse.

Now don't be argumentative. It was only the third costliest season on record.. [emoji849]

This thing just needed a little more latitude and could have easily been a June major. Could have played out similiar to a Felix based on the upper pattern. But as it stands now, though it may have just enough time to flirt with hurricane status prior to central American landfall, it needs to slow forward motion and develop an inner core fast. I never got too serious about PTC2 due to the low latitude track and interaction with SA, but now that it has cleared the SA landmass, got to watch for how fast genesis occurs today and if there is any slowdown in its trek over the SW Caribbean.

Norman...

CSU 4km WRF..

Really glad you finally scored a good snow. Also congrats to all who did well. I am happy with my paltry 2 inches south of Bristol. I am glad I checked hype and curbed expectations versus very consistent modeling of a snow hole over portions of Sullivan and Washington Counties. Modeling did exceptionally well. Pretty sweet that the NWS busted low for Knoxville as you folks were due a good thumping. Lastly, the event isn't over. In my mind I had interaction with bitter cold tonight as part of it. Really it's unusual enough to get such cold so near to Spring, and worth the continued discussion.

Two days of modeling and many noticeable precipitation holes over KTRI not to go ahead and expect that. Hopefully even if that occurs, there's enough mustard in this system to squeeze out 2-3 inches.

We're now within 100 hrs of modeling of a regional/forum wide Winter weather event. Probably a good time to go ahead and fire up a dedicated thread. For those wanting snow accumulations, good luck. This system does look decent on the majority of ops and ensembles right now in its positioning and timing for cold air to be in place. Totals on the other hand are still up in the air. We shall see how the week unfolds. Latest GFS operational...

Hrmmm...

Inject that straight into my veins. I'll gladly shut it down if that pans out.

RE: Mesoscale, HRRR is really cranking a band over the eastern Valley and Appalachians. That could easily produce 1-3" accumulation with high rates of just a few hours. We're getting into crunch time.