theweatherguy's website

Philadelphia Weekend Weather and Storm Forecasts
Glenn F. Schreiber DMD and Glenn Schreiber is theweatherguy writing about Philadelphia Weather [radar] [surface map] [disclaimer]
   

About this blog

theweatherguy's website,

"Thoughts and comments on Philadelphia Weather and Daily Life."

  • Glenn F Schreiber
    aka "theweatherguy"

  • Photos
  • Weather Definitions

  • RSS FEED
    Copy link for RSS feed

  • Links
    These are a few of my favorite links.

    National Weather Service

    Official Forecasts

    Meteorology Glossary

  • Archives

    Weather Archives:

  • 13: Jan Feb Mar Apr
    May Jun Jul Aug Sept Oct Nov Dec

    12: Jan Feb Mar Apr
    May Jun Jul Aug Sept Oct Nov Dec

    11: Jan Feb Mar Apr
    May Jun Jul Aug Sept Oct Nov Dec

    10: Jan Feb Mar Apr
    May Jun Jul Aug Sept Oct Nov Dec

    09: Jan Feb Mar Apr
    May Jun Jul Aug Sept Oct Nov Dec

    08: Jan Feb Mar Apr
    May Jun Jul Aug Sept Oct Nov Dec

    07: Jan Feb Mar Apr
    May
    Jun Jul Aug Sept Oct Nov Dec

    06: Jan Feb Mar Apr
    May
    Jun Jul Aug Sept Oct Nov Dec

    05: Apr May Jun July Aug Sept Oct Nov Dec

    Commentary:
    Miscellaneous

  • Find







  •        
    Thu, 31 Aug 2006

    Big change in Forecast - Thurs PM Revised
    My earlier discussion brought out the uncertainty of the current forecast based on giant differences between the NAM-WRF (zero precip) and the GFS (over 3 inches rain).

    The GFS has shown incredible consistency: Ernesto was going to punch into a high pressure ridge and bring us heavy rain, starting Friday afternoon. The NAM-WRF has Ernesto being shunted and blocked by very strong high pressure.

    For the short term, the NAM-WRF is verifying. High pressure is building into our area from the north and impeding rain from approaching. Confidence in either solution during the next 24 hours is unusually low. The older NGM model may have the right idea--high pressure blocks the rain for Friday, but the rains come in later. I'm going to go with a blend of the GFS/NAM and the old NGM model: which delays the rain until night.

    (Latest GFS just became available: still has rain starting Friday afternoon.) Fri 9/1: Cloudy...rains delayed until evening. Heavy rains develop at night.

    Sat 9/2: Rainy and windy. High 72.

    Sun 9/3: Lingering showers. Partial clearing in the afternoon. (Forecast uncertain)

    Mon 9/4: Partly sunny to mostly sunny. High 84 (Forecast uncertain).

    posted: Aug 31 2006 at 10:44 pm

    [/weather/aug06] permanent link

    Big change in Forecast - Thurs PM
    My earlier discussion brought out the uncertainty of the current forecast based on giant differences between the NAM-WRF (zero precip) and the GFS (over 3 inches rain).

    The GFS has shown incredible consistency: Ernesto was going to punch into a high pressure ridge and bring us heavy rain, starting Friday afternoon. The NAM-WRF has Ernesto being shunted and blocked by very strong high pressure.

    For the short term, the NAM-WRF is verifying. High pressure is building into our area from the north and impeding rain from approaching. Confidence in either solution during the next 24 hours is unusually low. The older NGM model may have the right idea--high pressure blocks the rain for Friday, but the rains come in on Saturday and linger. I'm going to go with the NGM model which delays the rain almost 18 hours.

    Fri 9/1: Partly/sunny cloudy in the morning, becoming cloudy late in the day. Heavy rains develop at night.

    Sat 9/2: Rainy and windy. High 72.

    Sun 9/3: Lingering showers. Partial clearing in the afternoon. (Forecast uncertain)

    Mon 9/4: Partly sunny to mostly sunny. High 84 (Forecast uncertain).

    posted: Aug 31 2006 at 9:51 pm

    [/weather/aug06] permanent link

    Quick Weather Update- Thurs Late Afternoon
    Looking at the latest model data....NOGAPS and GFS continue with heavy rains starting about 2PM and continuing into Saturday afternoon. Strangely, the NAM-WRF still has NO RAIN at all through Saturday. I'm continuing to ignore this, but I'm beginning to wonder if I'm ignoring something important. Hard to figure one model with zero and one with 3 inches of rain. With winter storms, this scenario sometimes turns out to be a total fizzler of predicted snowstorms. Gotta wonder if dire predictions of flooding rains is overdone?

    The trend is towards slightly slower/later onset with the heaviest amounts mostly occuring Friday night and lingering into Saturday afternoon now. Clearing delayed now and not expected on Saturday. If we go with NAM-WRF, it will rain late Saturday, but we're ignoring this.

    The GFS continues to be my preferred model in general, and the NOGAPS, my preferred model for tropical systems.

    Still not willing to commit to a forecast for Sunday, with so much short term uncertainty. The bike to NYC event may encounter some rain in NYC. I'll update later.

    posted: Aug 31 2006 at 4:54 pm

    [/weather/aug06] permanent link

    Quick Weather Update- Thurs AM
    Latest model data just coming available. The GFS continues with rain starting between 12-2 PM on Friday, although amounts are back up to those previously predicted. Trend is towards slightly slower/later onset with the heaviest amounts mostly occuring Friday night and lingering into Saturday afternoon now. Clearing delayed now and not expected on Saturday.

    The GFS continues to be my preferred model in general, and the NOGAPS, my preferred model for tropical systems.

    The WRF-NAM, which has been least consistent, has the storm lingering in the Carolinas and not affecting us until Saturday night. I'm currently ignoring the NAM model, with its known problems with tropical systems. However, the divergence of forecasts on this storm cannot be completely discounted. Confidence is not as high as I would like with the forecast.

    I'll update later when the NOGAPS and more data is available.

    posted: Aug 31 2006 at 12:55 pm

    [/weather/aug06] permanent link

    Reduction in Ernesto's Impact? - Thurs AM
    Some change with the forecast, based on last night's models. The GFS and NOGAPS continue to have the storm bring heavy rains to our area and the shore Friday through Saturday, although many of the tropical storm models have the center of the moisture moving into central and western PA, with little coastal development. This may mean that rains will be significantly less heavy (and winds significantly lower) than previously expected. Indeed, the 2AM run of the GFS model has precipitation totals way down, with under 2 inches instead of 4+.

    There is still uncertainty about how much clearing will occur on Sunday, as a blocking pattern and persistent moist flow may leave plenty of clouds and showers around. The NOGAPS and the GFS clear things out considerably, but the WRF-NAM has another area of low pressure bring showers on Sunday, especially coastal areas.

    Fri 9/1: Cloudy with rain developing in the late morning...then windy with heavy rains late afternoon into the night. Flooding possible although looking a bit less likely. High 76. Shore: Heavy rain and windy.

    Sat 9/2: Rains and wind taper off during the early afternoon. Some sun may break out in the afternoon. High 76. Shore: Rain ending mid-day. Some sun possible in the afternoon. Continued windy.

    Sun 9/3: Mostly cloudy, with some sunny breaks. Still chance of showers during the day. High 79. (Forecast uncertain).

    Mon 9/4: Partly sunny. Chance of showers along the coast in the afternoon. High 84 (Forecast uncertain).

    I'll update later!

    posted: Aug 31 2006 at 5:24 am

    [/weather/aug06] permanent link



    Disclaimer: I am not a meteorologist and provide this information as a hobby and for entertainment (mostly my own :-) . While attempts are made to predict the weather as best as I can, use at your own risk! I am NOT responsible for any direct or indirect consequential injury/damages due to your use of these forecasts. Always check the NWS Official Forecast for your final plans.

    The weatherguy.net home page has been visited times since October 2003.