MAG5035

Absolutely incredible viewing tonight. From the top of Tussey Mountain (NW Huntingdon Co) in Rothrock State Forest the aurora and its colors were easily viewable with the naked eye. With the moon having set earlier you couldn’t have asked for better sky conditions. Pics were taken about an hour ago. iPhone 15 Pro with 3-10 second exposure and no edits. I also got good videos of it moving and pulsing. f

I was just about to post, the aurora is already visible here. Gonna be a fantastic night to view it.

A lot of times a weakening storm won’t do as well at tapping the winds aloft to the surface, especially with dying or disorganized convection around the core. A deepening storm with explosive convective development are where you see the very high winds aloft translated to the surface efficiently. Every major hurricane is kind of unique in what it ultimately does in terms of wind/surge impact and how widespread the impacts are. Currently, the wind field of Milton is very confined.. owing to an extremely tight pressure gradient to go with its exceptionally low pressure. The 5pm advisory estimated the hurricane force wind field out only 25 nautical miles from the eye in all 4 quadrants, and 40 nautical miles for >50kts. TS force winds on 3/4 quadrants are 70-80nm with the NW quadrants out to 120nm. If this storm were impacting Florida right now in its current state, there would obviously be extreme damage and surge where the core of the storm impacted, but the absolute worst would be really confined. A “weaker” hurricane of this nature becomes a larger one. Instead of the extremely tight pressure gradient we have now, that pressure field expands and hence expands the wind field. When this is getting to the FL coast it could be one of those cases of maintaining a very low central pressure (for example a high end cat 4 pressure), but not necessarily focused cat 4-cat 5 winds. With that type of structure change could come a much larger field of weaker (but still destructive) hurricane force winds.. which would boost storm surge potential over a much bigger area along with the wind damage impacts. Time will tell how this eventually evolves with it’s structure, and if the forecast shear can weaken this more than expected in a better case scenario.. but this needs to be taken very seriously anywhere where there’s mandatory evacuations. The angle of attack of this coming eastward into the west coast of FL is a very bad one regardless when it comes to surge.

Have a feeling Steelers/Cowboys has a good chance at getting a lightning delay either prior to kickoff or early in the game with the incoming line of storms.

There certainly hasn’t been any kind of prolific rain rates, but today is the ninth consecutive day of recording measurable rainfall here… totalling 3.2” since 9/23.

Boy that was quite a sustained period of 2”+ per hour rates there. I had nothing like that rate wise, a lot of the time being under half an inch per hour and only a couple times it was briefly over an inch per hour (1.4/hr max rate). That saved this local area from seeing any real significant flooding issues this morning. My event total was still pretty much right at 3”, which was much needed here since I’ve missed just about every storm that has fired up nearby in the last few weeks. Despite all the rain last night and this morning, the yard is still solid enough for a mow with the sun out… maybe after the humidity drops. It’s cracked 80 here and the dewpoint is still about 73ºF.

PDS wording being used in the flash flood warning (emergency) statement issued a bit ago for Potter/western Tioga.

It seems the heaviest rain has shifted away from here but still moderate rates, which will likely linger for most of the morning. I’m at 2.92” so far for the event. Been breezy at times this morning, with a 31 mph gust registered about an hour ago. Wind shift occurred right around then as well.. from northerly to southeasterly. Gonna be heading out to see if there’s any local flooding issues. In my immediate backyard though this was a much needed rain and I didn’t register any excessive rates on the gauge overnight. This seemed modeled well by the HRRR from yesterday, when I had made my severe weather threat post. And that seems to be coming to fruition this morning in the Sus Valley with a main band with embedded severe winds/potential spinups and torrential rains. Mesoanalysis has the remnant low centered in Somerset County currently. Definitely ended up west of the NHC forecast track from this time yesterday.

Steady rain has arrived here. 70/70°F

It’ll depend on the track of the remnant low. If it follows what the NHC has for its track via the 8am advisory then best severe parameters likely would be just east of the Sus Valley. Most modelling I’ve looked at so far this morning though, global and high res, seem to have the remnant low of Debby tracking thru true central or even west central PA.

I’m kind of surprised SPC doesn’t have much in their outlook tomorrow for severe in Eastern PA. I feel like there’s a half decent severe threat (of the slight risk variety at least) for winds and brief spin ups. Using the new 12z HRRR here centered on 16z (noon) tomorrow, which I’ve noticed has really sped this event up. Simulated composite Radar: Screaming winds aloft at 850mb Very high helicity/shear, as per usual on the eastern side of a landfalling tropical system Modest but not excessive CAPE: Significant Tor parameter, which incorporates the shear and the CAPE So my interpretation is that the potential is there for severe issues for sure, especially if the HRRR take on having more of a distinct band/squall line is correct. CAPE is limiting factor on actually having cells capable of “significant tornadoes” but the parameter is spiked because of the very high low level shear/helicity. So I feel anything embedded in a band (or bands) will have the capability to bring some of the high winds aloft and potentially spin up some brief tornadoes. Didn’t include it with all the maps but even the 925mb wind speeds are modeled to be 50+ knots in the Sus Valley late morning tomorrow. Wouldn’t take much to mix it down. As mentioned before the HRRR looks faster with the progression than say the NAM. Could be too fast but it is a thing with TC remnants to move along once they’re interacting with a frontal boundary. That could be a limiting factor capping high end rain totals where the remnant core passes thru.

Some maps of note this morning. Updated flash flood guidance (6hr) Updated Susquehanna Basin Headwater guidance Of particular concern locally I have is with the Little Juniata and Frankstown branches of the Juniata River. These tributaries have some of the most attainable numbers for moderate and major flood categories and they’re colocated with the modeled passage of the remnant core of Debby, where these 3-5” totals are most likely (and likely most of that coming within 6-8hrs). I’ve personally had only 2.3” of rain in the last 30 days, with only 1.25” falling in the last 2 weeks… but 5-10 miles from here has been a completely different story with last Saturday and Tuesday having storms that have dumped 2-3” both times in the areas that cover a good part of the basins of those two tributaries.

Still a good bit to be determined with regards to now Hurricane Debby’s eventual track/progression into the southeastern US and presumably further up the eastern seaboard this week. The certainty at this point is that this is likely to be an extremely prolific rainmaker in FL/GA/SC/NC. Most guidance tries to bring Debby back out into water off the GA/SC coast before making a second landfall, and then becomes the issue of what it does after that. There’s no real strong trough diving down to pick this up or anything, so it will be slow moving/meandering for a good portion of the week. I suspect the most likely scenario is it eventually gets drawn up the east coast late in the week in some fashion as generally suggested by the Euro/Canadian/ICON, etc. The GFS has been basically sending Debby directly back where it came from after it emerges off the GA coast and then stalling further towards AL and the FL panhandle. A possibility but probably a less likely scenario. In terms of eventual direct C-PA impacts. The Euro suite (op/ensemble/AI version) currently seem most supportive of the more traditional tropical remnant swath of precip tracking thru a fairly sizable portion of C-PA (best chances for bigger totals in the Sus Valley portion). The GFS/GEFS despite its unusual tracking would still eventually draw up significant moisture into PA anyways but not the remnant low itself. In the meantime we have a shortwave rounding the top of the ridge that will provide shower/thunderstorm chances centered on Tuesday night, as the ridge is centered west this week and we are positioned on the rim. This additionally could provide a swath of heavier rainfall somewhere in C-PA in the form of a more organized cluster of storms. This feature also probably figures to influence Debby’s track in some form as well, likely drawing her track back NW. But at the least, this feature provides the best chance of rain this week for western and central PA, where the current probabilities of significant rain from Debby’s remnants are less than that of the eastern third.

Been on a pretty rough run here at the IMBY level, if something fires up around here the last few weeks it finds a way to miss. 0.08” on the day and 0.46” last 7 days.

Sorry I haven’t posted much lately, I usually am busier during the spring and summer months but this year I’ve been especially so and haven’t had much of a chance to post. But otherwise all is well. It has definitely been hot enough haha. I’ve already had about 12 days of 90+ this summer to date here at home, with a max of 95ºF (twice) and several other days that were 88-89ish. Probably a fall breeze compared to some of the LSV this summer but definitely hot for this area. Only about 0.6” in rain since 6/28 and 0.44” of that came on 7/3. Hopefully that changes this week.