If you are using the v5.0x forecast script, you are prone to anomalies because the underlying NWS service is still in beta. You can contact the NWS office via the info given to let them know that their "new API" forecast is out of date.
If you don't want to deal with issues of the forecast being old or unavailable, stick with the v4.0x version of the forecast script.
(Ken, maybe we should have a sticky thread at the top to remind people of this...)