Notes on Current Stations, Fall 2016


Traverse City, MI (KTVC)

  • notes

Reno, NV (KRNO)

  • strongest winds from south and west (due to valleys being in those directions); mountains to west/southwest, 30-40 km away.  pretty dry this time of year, though October got a lot of rain.
  • MOS much better than 2m, possibly because models have trouble resolving valley.  However, MOS worse in rain/high wind conditions.  2m low seems too high during clear days.

Grand Island, NE (KGRI)

  • southeast of hills, but pretty flat overall.  airport not super close to a river
  • probably dry, moderately warm this week (10/24)?  probably too windy for the lows to get too cold, even though likely to be clear
  • tonight: low system forming and passing by, all the rain likely to the east though
  • NAM mostly good on highs/lows, but a few really bad lows (those days had low on the second 6Z, were clear, and NAM was too high).  GFS did the same, though GFS seems to be too high generally (for lows), though GFS MOS pretty good on low.
  • Those two days with 6Z low also had MOS winds that were way too low.
  • GFS (on lows, also highs) seems biased high
  • “marginal”: 5% chance of severe thunderstorm
  • scientific forecaster discussion: we’re somewhere in the middle (pretty close to Hastings)
  • fog/cloud cover in the morning could make it harder for thunderstorms to form.  (70 roughly, 50 roughly, 15-20)

Harrisburg, PA (KMDT)

  • Actual weather station is right next to the river; possibly resulting in weird temperature issues (i.e. temperature didn’t change much overnight for a really long time, then dropped all of a sudden)
  • September was unusually warm, the soil temperatures are also warmer than usual.  Might be affecting radiative cooling, which doesn’t seemed to have cooled the temperatures as much as might have been expected
  • Located in a valley close to mountains, could potentially get very high winds.  Based on model forecasts for 10/13, mountains might be a bit of a barrier to precip for fronts coming in from the west.
  • Fairly uniform precipitation amounts year-round, though mode of precip changes (mostly convective in summer, switching to synoptic around October)


Key West, FL (KEYW)

  • September is one of rainiest months
  • island is smaller than the grid scale of the model…
  • ocean temps are 3 degrees warmer than usual right now; was 90 today though climatology suggests that’s not frequent.  Very shallow water nearby.
  • climatology winds annoying because stronger winds associated with thunderstorms.
  • reading climo precip on Brian Tang’s page: on days when there is precipitation, avg (dotted black line) is about 0.4″
  • island is rectangular, roughly 4mi x 1mi; maybe enough to create a seabreeze? Tim says it’s small for a substantial seabreeze, probably shallow.
  • SSTs generally drop ~4 degrees over the whole month of October, not likely to change that much over forecast period.  SSTs affected by meanders in the Gulf Stream though
  • question: when does MOS switch from summer to winter mode?  maybe in October
  • GFS 2m is missing diurnal cycle because there’s too much water, missing land entirely?  JS: “2m is useless for this station”
  • general strategy, maybe try persistence/climatology but watch out for convective storms (lower temperature and higher wind).  watch out: model/MOS winds are for background, not taking storms into account (might get gusts).
  • Vince: more likely to have precipitation early in the morning?  this tends to be the case over tropical oceans, also weak diurnal cycle.
  • GFS MOS doing okay with highs; probably not going to vary too much though (ranges around 89?)
  • Jet stream too far north to affect KEYW too much (perhaps minor influence from northern/continental US weather pattern); probs best to go with climatology and deviate a bit from that.  if I think it’s going to rain, pick slightly lower temperature and higher wind.
  • question: what’s a stacked low system? apparently getting slowly advected east
  • apparently right now large-scale pattern looks a little like how it did the dry week.  however, have tropical wave (low in eastern Gulf)
  • NWS has issued flood advisory today (9/26) through Wednesday
  • 89 likely high; low 77/78 if not raining; 80?
  • Dan Gilford: >30%, tend towards rain.  also from radar looks like rain tonight (9/26)
  • also try to look at model map and see if there’s a large-scale feature that it’s trying to focus precipitation on?

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